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The prevalence of impaired glucose metabolism in Hispanics with two or more risk factors for metabolic syndrome in the primary care setting. J Am Acad Nurse Pract. 21:173-178. Neira CP, Hartig M, Cowan PA, Velasquez-Mieyer PA.(2009).
Claudia P. Neira, DNP, FNP is the Clinical Coordinator behind this study, Margaret Hartig, PhD, APRN is an Associate Professor at the University of Tennessee College of Nursing, Patricia A.Cowan, PhD, RN is also an Associate Professor at the same institution, and Pedro A. Velasquez-Mieyer, MD is an Associate Professor of Pediatrics at the Division of Endocrinology and Metabolism at the University of Tennessee and a Medical Director at the clinic LifeDOC. The authors all work for the University of Tennessee and an affiliated clinic in Memphis [Lifestyle Diabetes and Obesity Care (LifeDOC)] that specializes in the treatment and follow up/coaching of patients with diabetes and obesity. The authors also originate from the University of Tennessee's Health science center and it is apparent that they have a broad range of experience both in generalized primary care and in the treatment of diabetes in particular.
The title of the article is well written and concise. One can easily deduct the purpose of the study reported in the article and although it comprises of more than one key medical expertise terms, such as diabetes and metabolic syndrome, the authors have chosen clarity over shortness, thus having analyzed the term diabetes in its meaning i.e. impaired glucose metabolism (IGM), to reach their specific audience. Also the term impaired glucose metabolism includes patients that can even have a normal fasting glucose, thus showing a broader investigative content. It is not until the end of the article however, that we are informed of the definition of IGM as an intermediate category between normal glucose metabolism and inert diabetes mellitus type-II. The title does not prepare the reader for a major part of the article presented since it only mentions the "prevalence" of IGM in Hispanic patients, whereas the authors have conducted a much more thorough investigation of the multiple interactions between cardiovascular and inflammatory risk factors. This can be considered a limitation when assessing the accuracy of this paper's title.
The abstract is structured in an unconventional way, substituting where one would expect "results" with "conclusions". However, it is well presented and very detailed in all major findings of the study presented therein. The implications for practice section underlines the importance of the results for practice, however one gets the impression that these were findings that were unprecedented in the medical literature. Suspicion is raised and the reader awaits the main text of the article to decide whether the implications for practice arise only after the results of the present study or make part of a wider research frame directed at the special population of Hispanics.
Research Problem Purpose and Significance
Diabetes is an important cause of mortality and its complications affect a wide number of patients in the USA and worldwide. The prevalence of diabetes or IGM in Hispanics has been reported by the CDC ( CDC,2003 ) to be elevated 1.8-fold. The increase in the prevalence of diabetes is found more in minorities. The metabolic syndrome on the other hand is determined by a wide variety of risk factors that lead to the development of cardiovascular disease. It is associated with the development of type-II diabetes. One of the risk factors is diabetes and the rest include increases waist circumference (high body mass index-BMI), hypertension, microalbuminuria, elevated TG or low HDL. The authors report of a study that has discovered increased rates of the metabolic syndrome in Hispanics. The authors also report that there are significant factors further in the assessment of the metabolic syndrome, such as cardiometabolic risk factors (CMRF) : additional lipid abnormalities, markers of inflammation and lifestyle or genetic factors that are significantly important for the progression towards cardiovascular disease and diabetes. A last point, made towards the determination of the research focus, is that primary health care providers can make a difference in the management of diabetes and specifically in identifying risk factors for its prevention. Hence, it is important to search for predictors of IGM and diabetes in Hispanics in the primary care setting.
The problem seems to be appropriately limited in scope for the design of a focused study that aims to assess separate and distinct research findings. It appears that the authors have identified an area that lacks research outcomes and this is the evaluation of additional CMRF for the identification and prevention of diabetes in Hispanic patients. Since the target group appears to have higher prevalence rates (cited by the CDC), this aim seems noble and specific in its scope. A wider target group therefore would have been redundant. Also, the authors decide to embark on a question for specific markers that have not been previously assessed, and that makes the study clear with direct practical evaluation of its results in primary care.
The goals of the study are put down by the authors as: a) to measure the prevalence of IGM in Hispanic patients that present in primary care and have two or more factors of metabolic syndrome. b)the examination of the relationship between glucose metabolism and CMRF, including metabolic syndrome components c)the examination of the research hypothesis that CMRFs such as total cholesterol, LDL cholesterol and CRP-hs (high sensitivity C-reactive protein) levels are able to determine patients at high risk for IGM. It appears that the authors are parallel in their goals with the purpose outlined in the abstract and introduction of their study. However, the authors state that the purpose was (corresponding to their goal number 3) to identify predictors for IGM. This is partially the case for the predictors that the authors have arbitrarily (although by predetermined criteria) chosen for their research. In this case the purpose has narrowed down the goals, but this does not mean that the predictors that this study will identify are the only ones there, for IGM.
The study seems feasible to conduct in terms of costs and researcher's expertise .It is being conducted in a well organised purposed clinic, in a University environment, which means that the subjects would normally be patients frequenting this setting. To account for any selection bias in the designation of the research sample, patients with a known history of heart disease or diabetes were excluded. Also, the study employed bilingual researchers which seems very convenient but can not be further assessed as to its generalizability, perhaps since this option was readily available at this particular setting. Also, as an observational prospective study, it seems very simple to conduct with direct measurements of a primary care level (height, weight, blood pressure, fasting blood glucose levels) and data collection made easy with the use of computerized medical records.
Review of Literature
Many relevant previous studies are described and critiqued. In the introduction section, the authors have already documented the following, by literature review:
a) the importance of diabetes and its complications (1 study)
b) the high prevalence of diabetes or IGM in Hispanics- reported by the CDC and as part of the high prevalence in minorities(1 study-CDC)
c) the importance of the metabolic syndrome (2 studies)
d) the link between metabolic syndrome and diabetes mellitus (1 study)
e) the prevalence of metabolic syndrome in the Hispanic population (1 study)
f) the American Diabetes Association recommendation for the estimation of further CMRF to compliment the assessment of metabolic syndrome in the risk of developing diabetes
g) the feasibility of the interventions at the primary care level aimed at the early identification of diabetes in halting this epidemic (1 study)
In their results section, the prevalence of IGM in their 55 subjects is compared with the finding from one other study, by the National Health and Nutrition Survey 1999-2002. A critique is made on the difference observed between the two studies. Also, in their estimation of IGM and CMRFs they present with evidence from previous studies that suggest that the metabolic syndrome predicts future risk of diabetes type II-mellitus (3 studies). Obesity is also documented by one study to favour the onset of metabolic syndrome (2 studies) in particular central adiposity (Appel et al, 2004). This is counter-projected to the study population where likewise, high BMI was found to be the most prevalent metabolic syndrome marker. However, since the study was directed against Hispanics and not the Caucasian populace, cut off levels for BMI from the WHO,2007 are not considered as appropriate (1 study).The authors excuse in detail their final decision to use the current WHO and NIH cut offs ( the cut offs for Hispanics are considered lower for the development of cardiovascular disease and diabetes- however this would only exaggerate the current research findings, since variety in body proportions are thought to arise in all different populations).
In the assessment of metabolic syndrome and inflammation the authors make several comparisons to relevant previous research, such as the possibility to predict the incidence of diabetes by measuring CMRFs, the American Diabetes association guidelines, the role of inflammation in the development of diabetes(1 study), the role of CRP as an inflammatory marker in the estimation of the risk for developing diabetes ( 2 studies),metabolic syndrome ( 1 study) or for estimating cardiovascular events ( 4 studies). CRP is also referenced in its role in estimating insulin sensitivity ( 1 study). Previous reports have found elevated CRP levels in high BMI and females (Diabetes Prevention Program Research Group). Findings such as concurrent HDL low levels and elevated TG levels with obesity are found by previous reports to be significant worse in the risk for cardiovascular disease ( 1 study). Early intervention is sought as capable to prevent or postpone diabetes mellitus in these patients ( 1 study).
The studies cross referenced by the article are all current to the articles' publish date and are all in the range of 1998-2007. This is considered a high value for any research article in the primary care domain where knowledge is growing rapidly and especially in diabetes prevention that affects millions everyday.
The literature review has described the knowledge base about the specific risk factors in an extended and detailed way. There is no issue left uncovered in the investigation of the role of the various factors in the development of diabetes, and this is step by step proved in the above detailed analysis of the references. One could however argue that the research focus is specific and does not include the measurement of other factors initially implicated as predictors of IGM and diabetes such as lifestyle factors ( i.e.smoking, lack of exercise) and other lipid abnormalities such as ApoB. This distinction probably lies in the limitations and materials available for the current study and can not suffice for its characterization as incomplete. Also, one might argue that the authors have not recognised in their article the knowledge base of concurrent diseases that could lead to the high measurements of the perceived risk factors. We are not made aware of other concurrent conditions such as for example acute infections that can lead to a high CRP value, or any pertaining literature that distinguishes between high CRP in diabetes and high CRP in other conditions.
The review is very well organised and follows the structure of the results and hypothesis tested to reach the desired conclusions as well as the development of the scientific knowledge behind the tested hypothesis (time-wise). This is also apparent from the previous detailed reference of the reviewed components in this present critique. The introduction comprises of statements pertinent to the wider research question in a timely consequence, while other questions are being assessed and compared thoroughly in the stream of the presentation of the results. It was found however highly contradictory to discuss throughout the paper of the sense of IGM, while only at the last page in the conclusion section, is the theoretical base for distinction of IGM and inert diabetes, made. This could be due to the more recent implication of this distinction (2001) that has established this new measurement. The reasonable source and timely coherence between research findings is observed throughout. However, researchers have failed to identify any contradictory research findings between the reviewed evidence in the course of time.
The literature review provides with a detailed thematic support of the research focus question and key variables, as shown in the detailed analysis.
The study uses theoretical background from various sources and this can prove to be an obstacle in the comprehension of the study outcomes. It is true that when using multiple guidelines and comparing the previous literature the authors have chosen to interpret others as valid and others as not valid for the purposes of their study. For example they acknowledge that different BMI cut offs exist for the Hispanics but they choose not to use them, in fear of the major variability noted in several populations (WHO ,2007) that could reduce the internal validity of their present study. The most wide however theoretical backgrounds are provided by valid sources such as the CDC, the Americal Diabetes Association , the WHO, the Insulin Resistance and Atherosclerosis Study (IRAS) and the National Institute of Health.
In brief one could limit the theoretical framework in the following sentence: "Diabetes is more prevalent in Hispanics, as is the metabolic syndrome. Impaired glucose tolerance is widely used to test for disposition towards development of diabetes. Various factors such as the CMRFs are sought to play an important role in estimating the risk for the onset of metabolic syndrome and diabetes." This summarizes the necessary theories backing the study, and are all derived from the medical and nursing basic knowledge base, hence no other theoretical framework is deemed necessary. The theoretical framework as is, is very well presented, represented and outlined in all parts of the study.
It is also interrelated with the purpose of this study. Another relevant framework could possibly be to assess the cardio-metabolic risk factors (CRMFs) separately and then progressively check for the development of diabetes in the tested subjects. This however, would have been highly unethical since it would provide that none of the patients would receive treatment for the prevention of the diabetes, diabetes being an anticipated research outcome. This, in a Health Science institution is unethical and would be a framework possible to be used only by a retrospective study, to adhere to the above ethical considerations.
Research Questions or Hypotheses
The research questions and hypotheses are clearly stated both in the abstract and the introduction of the article, reasonably put after the relevant literature review. These are: a) to measure the prevalence of IGM in Hispanic patients that present in primary care and have two or more factors of metabolic syndrome. b)the examination of the relationship between glucose metabolism and CMRF, including metabolic syndrome components c)the examination of the research hypothesis that CMRFs such as total cholesterol, LDL cholesterol and CRP-hs (high sensitivity C-reactive protein) levels are able to determine patients at high risk for IGM. They are considered concise and well-structured for an observational pilot study.
The research questions are parallel to the research purpose which is to identify earlier and by more factors, the onset of diabetes in patients with an Hispanic descent. For this purpose, the authors have selected easy-to-measure, convenient, routine markers such as hs-CRP. Therefore, the authors proceed to investigate the relative power of these markers to identify patients with IGM to provide with a feasibility analysis for the use of this marker in routine primary care. This is a reasonable design with an adequate research sample size (55 subjects).
The hypotheses are also inherently linked to the theoretical framework, since CRP for example is a wider inflammation marker that has been linked to the development of cardiovascular disease and as such can be considered a CMRF leading to metabolic syndrome.
The study variables of the present study are :
* Hispanic descent
* (Clinical characteristics) :Age, Gender, Systolic blood pressure, Diastolic blood pressure Weight (kg) BMI (kg/m2)
* (Laboratory results) TC (mg/dL),LDL (mg/dL) HDL (mg/dL) TG (mg/dL) CRP-hs (mg/L) Glucose at 0 min and Glucose at 120 min, CMRF (estimate of risk)
The dependent variables are the presence or absence of impaired glucose metabolism ( pathologic values of glucose at 0 min and Glucose at 120 min) and they were easily identified as the values that are of direct interest to the research purpose. These values were dependent to the metabolic system of the affected individuals and were assessed by using the same quantity of glucose ingested by all subjects and respecting the same experiments conditions for all subjects.
Independent variables are all variables, studied for having or not having an effect when they coexist with the dependent variable. All other variables are independent in this study.
Extraneous variables are for example the Hispanic descent. This has been controlled for in this study by using bilingual researchers administering the research protocol on subjects, to avoid any other extraneous variables from appearing such as racial discrimination, anguish on part of the subjects and conditioning of their behavior.
The variables are clearly identified by the authors as well as the reader, from the initial glance at the article, since the dependent variables are well distinguished in the title. However, some of the independent variables appear later in the analysis. This could have been, in our humble opinion, avoided.
All the variables have been clearly defined, with extensive literature reviews on the effects that were anticipated and a detailed analysis of the results actually found. Also, the methods section implies the used measures for the avoidance of extraneous variables, which is conceptually derived by the reader as such.
The variables bear a logical connection to the research purpose and theoretical background. The choice of markers has been at the author's discretion. We believe that many others could have been equally investigated but this is at the discretion of the authors according to the means available for the study. This refers to the choice of CRP for example and not the ApoB, in the estimation of diabetes predisposition.
The variables however are found inherent to the theoretical context and framework, are well acknowledged and widely used markers in primary care that are easy to obtain and thus, constitute a feasible instrument for the research purpose.
Part # 2
The authors clearly state having obtained the approval of an Institutional Review Board.
The subjects were subjected to various measurements that can be considered as "normal procedures" and in the clinical examination scale. Also, the authors tried to minimize discomfort by i.e. inserting a catheter to make their blood measurements, and this although painful substitutes for a much worse discomfort of multiple venipunctures for the subsequent measurement in 120 minutes. In all, subjects seem to have not suffered since the research experiment is basic and no drugs are administered.
The researchers do not provide with the methodology used to recruit the subjects or to convince them for the benefits versus risks for participating in the study. However, with the measurements being mostly venipuncture and the results being the estimation of predisposition to diabetes, one could comprehend that the subjects could outweigh the discomfort of testing since they would be provided with a health assessment which was probably free.
Informed consent was provided and was requested in the subjects' original language (Spanish). When adolescents were involved, consent was also requested from the authorized representatives or parents. No other vulnerable groups were involved. These measures are thought to be adequate for this study design and hypotheses.
This design is very flexible to allow for any research question to be assessed since it is a case study of a specific group of people studied to predict the onset of diabetes. Thus, as an observational study, the effect between the variables for example CRP and BMI is investigated easily through the design. However, one could argue that the validity of the study would be greater for findings that have not been previously proved, not even in the general population, had a control group been utilized. This is true and is a limitation of the above study. Hence, its findings can only be extrapolated to distinct Hispanic descent groups. Also, the design has left the options readily available for the researchers, to choose the subjects according to previous history, while exclusion criteria are carefully laid down for the reader. This is crucial for the comprehension of the results.
The above study measured IGM as an independent variable that would lead to the administration of treatment. However, this is not clearly identified in the paper. It is true, that patients taking part in this study were assessed in their course of investigation leading to the administration of treatment or follow up for the monitoring of diabetes. All patients that were identified as problematic are assumed to have received treatment at the end of the study.
Impaired glucose metabolism that was the independent variable of the research protocol, was assessed by administering a research protocol that was consistent among the tested subjects. Had the protocol not been monitored, various discrepancies in the results and the subsequent search for etiologic correlation would have been found. Thus, the study would not be valid.
Threats to internal and external validity are biases that exist in the study design and diminish the accuracy of the results in terms of inherent flaws in design (Internal) and applicability-significance of findings (External). Threats were obviously identified by the authors. A significant threat to external validity is that the study setting is that of a tertiary referral site that is bound to have more problematic patients than a primary care centre. It seems that a significant selection bias was also imposed, by excluding already suffering by various diseases patients that can alter the research findings especially those with a concurrent heart problem that could even serve as a comparison in the estimation of cardio metabolic risk factors. Also, a statistical regression bias is apparent when selecting groups that have extreme characteristics (in this case Hispanic descent). Hence, results are only generalizable to the Hispanic descent group of patients (external validity threat). Instrumentation seems also to be controlled for, since standard procedures were used for all subjects. Testing threats such as language differences were accounted for by using Spanish speaking researchers, thus not affecting the pro-test post-test situation of the subjects.
The use of a control group is redundant since the study design is observational and no intervention is being made other than the monitoring of glucose level. This could be a testing bias, but a minor one.
The setting is that of a University endowed clinic with a special interest in diabetes and obesity research. It is however not described in the present paper.
4. Sampling Process
Patients were referred to the UT-LifeDoc clinic after being identified for having two or more of the risk factors associated with the Metabolic Syndrome (BMI >25 kg/m2, elevated TG, low HDL cholesterol, elevated blood pressure, elevated fasting blood glucose, and elevated
CRP-hs). Patients included should be aged 14yrs old and older and be of Hispanic descent. Also, patients with concurrent heart, liver, kidney disease, pregnant women, or patients taking medications affecting glucose metabolism were excluded from the analysis. In all, 55 patients met the inclusion criteria and were included in the study.
The sampling method was not randomized but rather ordinate. Characteristics of the study population included mean age 33.6 ÂÂ± 1.8 years and 60% female. This means that, according to the authors' literature review that states that females have a higher likelihood of having elevated CRP levels, the power of the study to determine one of its posed hypotheses is weakened by the presence of slightly more women than men. A representative sample according to the setting of the study is found, however, by no means is it representative to other Hispanic group samples found i.e. in primary care. A better approach would be to randomly select Hispanic males and females ( equally) from the general population that are likely to visit a primary care provider and not a tertiary university clinic.
The biases are therefore, an institutional bias ( select population) and a statistical regression bias ( extreme characteristic bias). The exclusion criteria are rational and allow for a clean and concise determination of the research goals. However, it would constitute a much more representative study sample to include Hispanics with already present heart diseases to better represent the prevalence in this population.
According to this setting and the resources of the authors an appropriate design has been utilised. A control group is not appropriate when there is no intervention. Thus, an observational analysis is in place, however, study limitations should always be mentioned to allow for an extrapolation of results.
The study sample seems sufficient for the representation of Hispanic males and females referred to tertiary care for the assessment of metabolic disease. Power analysis however is not used or population dynamics analysed. It seems that this was the number of the Hispanic patients available at the time of the study. The refusal rate did not seem to pose a problem neither did sample mortality or attrition.
A 2-h 75-g oral glucose tolerance test (OGTT), a calibrated electronic scale (Detecto , Webb City, MO) for weight measurements , a mercury sphygmomanometer for systolic and diastolic blood pressure, spectrophotometry for the estimation of lipids and the Friedewald formula for LDL and latex immunonephelometry for the estimation of CRP were used as measurements for this study. Sufficient information is provided for scoring and universally approved values of measurement.
It is true that many modern biochemical analyst consoles could better provide measurements for lipids and LDL for this study as well as the CRP (Williams,2000), based on immuno-enzymical methods. However, the methods employed (how old they might be- since no information is given), can also provide with accurate measurements and acceptable reliability and validity. One could argue, however that automatic consoles are deemed much more reliable than manual estimation on latex rapid tests.
6. Data collection
Data collection was performed by the principal investigator of this study using the software of the medical data base used for this study. It is referenced and clearly described. Training in data collection is not mentioned, problems that could have arisen are stratification errors, data handling errors and analysis errors. This method however simplified is consistent throughout the study population and addresses all the research goals, even by employing formulas ( LDL estimation ) for the estimation of indirect lipid fractions, or stratifying by amount ( number) of risk factors (CMRFs). No further information is granted concerning data collection.
Part # 3
The authors used the SAS statistical software program (version 9.1) for data analysis with statistical significance at p< .05. The methods used were descriptive statistics for the study samples' characteristics. Wilcoxon tests and double square chi test were used to perform comparisons between the different IGM groups and the normal tolerance to glucose group.
To estimate the relation between glucose metabolism and CMRFs, Spearmans' correlational coefficients were used. To end, logistic multiple regression analysis was used to identify predictors of IGM by calculation Odds ratio's (OD) and Confidence Intervals (CI).
The data analysis techniques are clearly defined and analysed. They are also deemed appropriate for the research goals and the type of sample used in the analysis. Also, the authors used non parametrical statistics to avoid error type I since the study sample was small. In detail, the authors did a good job choosing their statistical tests.
The data analysis results are interpreted cautiously and appropriately. Tables are present and narrative explanations provided to all material presented. The authors also have an illustrative figure.
2. Interpretation of Findings
All findings are discussed in relation to the research questions posed at the beginning of the article. In detail, the authors find 46% of patients with IGM, of which 48% had normal fasting glucose. The mean number of cardiometabolic risk factors (CMRF) was 4.5. Mean values for each risk factor were not different between glucose metabolism dependent groups except for number of CMRF (p = .0001) and TG (p = .0001). The total number of CMRF was the best predictor of IGM. Also, inflammatory markers such as the CRP was not found significantly correlated with IGM.
All findings have appropriate explanations. When CRP is not found positively correlated with IGM, in the research of metabolic syndrome and inflammation, the authors explain that more research is warranted in this area.
The findings are somewhat consistent with previous studies. However, the 46% of IGM in Hispanic subjects is found controversial to another study that had found 32% of IGM in Mexican Americans. However, we note that this second study included patients that belonged in the general population and had not been referred for further investigation as the subjects in the present study. They also find that 61% of the participants were obese and 29% were overweight. This is not compared to other studies. Ninety-eight percent of the Hispanic participants
of this study had abnormal lipid values, such as elevated TG (66%) and low HDL (67.9%), which are both components of the metabolic syndrome. This is thought to account for a much greater risk for cardiovascular disease. No other studies have measured the correlation of CRP and IGM that is being known to the authors at the time of the study.
The findings are linked to the study's framework and are interrelated to the study of cardiovascular and diabetes risk, with a specific aim at their prevention. In detail, the authors goal is to provide with a reliable measurement of risk factors that will aid primary care physicians (PCPs) to assess with greater attention Hispanic patients in danger of metabolic syndrome and diabetes.
The researchers' conclusions flow directly from the analysis of the results and are intercalated with research implications from major associations and groups.
The findings are clinically significant as to the extent that they can be easily identifiable to the primary care physician in the identification and early prevention of diabetic disease.
The authors do not describe their limitations which is a major shortfall of this article. The article has a relatively small sample population, it is specialized due to the referral status of the patients and also is not generalisable to the Hispanic minority. The result of a high (48%) number of normal glucose levels among the pathological IGMs, should have worried the authors apart from giving them significant cause in their support of vigilance in PCP diagnosis. A limitation stating the implication of this finding in larger populations where normal glucose levels are monitored but no other CMRF factors are taken into account should have been more extensive. However, most implications of findings are true and are appropriately based ( PCP awareness, need for multiple factors). Appropriate suggestions for future research have been made in the text and the end of the article, regarding the relation of CRP with IGM and also the position of the primary care practitioners in identifying type-II diabetes mellitus.
3. Evaluation of the Study:
The findings of prior studies have reasonably generated a research problem in the evaluation of patients in need for diabetes prevention and/or estimation and follow up. This is made readily available for the reader in all sections of the article, where we realise that significant research has been oriented at the estimation of the best predictive risk factors for early recognition of IGM and/or inert diabetes type-II. This design is a contribution to prior studies in this area, since it offers with an evaluation of a specific subsample of the general population that suffers from increased prevalences of predisposing factors, risk factors and disease. It provides with a second best reference for the estimation of the prevalence of IGM and diabetes in Hispanics. Also, it provides with a first evaluation of a regression analysis proving that the estimation of CMRFs is the best predictor in identifying diabetes predisposition. Sampling strategy is very simple and as such is not a significant advancement but rather a less important contribution. Taking into account the study characteristics, one can say that this study provides with a background for a more detailed research strategy in either the same or more general populations. Statistical analyses however, were extensive and highly valued compared to previous studies since a lot of the characteristics of the study population were controlled thus allowing for a solid regression analysis for the identification of predisposing risk factors.
The research design and quality of the article was consistent in purpose and rationale. All components of the hypotheses reasonably linked together to form a rigid research question and evaluation. It is my personal opinion that more inflammatory markers could have been used to allow for a better estimation of the role of inflammation markers in the metabolic syndrome, other than the CRP (such as ApoB). This would serve as an economy for scale measurement and could easily fit in the data analysis already in pace for the study. And this addition would only offer stronger evaluation, since none of the other compontnets would have to be modified.
The study is well presented and conducted carefully. Enough caution should be placed when evaluating the implications of these findings, since the study selection seems to be biased towards a study sample that inherently is at risk for more cardiovascular disease and diabetes ( due to the already seeking of healthcare utilization). This means that their findings can only be extrapolated to patients seeking referral services, and not to the general population. Also, the authors have failed to identify their limitations, making it very hard for the reader to carefully identify them and thus account for their correction. Implications of practice however are carefully acknowledged and consistent with the research goal, although as stated above a little over estimated.
Overall, this was a well conducted and important original research study, which provided with a backbone analysis of the prevalence of IGM and diabetes mellitus in Hispanic patients that sought treatment for multiple metabolic syndrome factors. The authors managed to analyse and measure statistically the amount of factors needed to precisely account for a higher risk of dys-glycaemia, which can then serve as a useful instrument for primary care physicians when investigating patients from this suffering population group.
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Centers for Disease Control and Prevention. (2003). Prevalence of diabetes and
impaired fasting glucose in adultsââ‚¬"United States, 1999-2000. MMWR Morbidity
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World Health Organization. (2007). Global database on body mass index. Retrieved
December 3, 2007, from http://www.who.int/bmi/index.jsp?introPage=intro_3.html
Barbara Ohlund and Chong-ho Yu, 2009 "Threats to validity of Research Design" .
Assessed online on February 21, 2009 at http://www.creative-wisdom.com /teaching /WBI/threat.shtml
William L. Roberts, Rachel Sedrick, Linda Moulton, Anthony Spencer, and Nader Rifai
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