[Variability in the calculation of coronary risk in type-2 diabetes mellitus]

Research inefficiencies in external validation studies of the Framingham Wilson coronary heart disease risk rule: A systematic review

BACKGROUND

External validation studies create evidence about a clinical prediction rule's (CPR's) generalizability by evaluating and updating the CPR in populations different from those used in the derivation, and also by contributing to estimating its overall performance when meta-analysed in a systematic review. While most cardiovascular CPRs do not have any external validation, some CPRs have been externally validated repeatedly. Hence, we examined whether external validation studies of the Framingham Wilson coronary heart disease (CHD) risk rule contributed to generating evidence to their full potential.

METHODS

A forward citation search of the Framingham Wilson CHD risk rule's derivation study was conducted to identify studies that evaluated the Framingham Wilson CHD risk rule in different populations. For external validation studies of the Framingham Wilson CHD risk rule, we examined whether authors updated the Framingham Wilson CHD risk rule when it performed poorly. We also assessed the contribution of external validation studies to understanding the Predicted/Observed (P/O) event ratio and c statistic of the Framingham Wilson CHD risk rule.

RESULTS

We identified 98 studies that evaluated the Framingham Wilson CHD risk rule; 40 of which were external validation studies. Of these 40 studies, 27 (67.5%) concluded the Framingham Wilson CHD risk rule performed poorly but did not update it. Of 23 external validation studies conducted with data that could be included in meta-analyses, 13 (56.5%) could not fully contribute to the meta-analyses of P/O ratio and/or c statistic because these performance measures were neither reported nor could be calculated from provided data.

DISCUSSION

Most external validation studies failed to generate evidence about the Framingham Wilson CHD risk rule's generalizability to their full potential. Researchers might increase the value of external validation studies by presenting all relevant performance measures and by updating the CPR when it performs poorly.

Cardiovascular risk and validation of cardiovascular risk prediction functions in a cohort of patients with type 2 diabetes followed for 10 years in Badajoz (SPAIN). AN observational study

AIMS

To analyse whether diabetes behaves as an equivalent of coronary risk and assess the performance of the original and REGICOR Framingham functions in a cohort of patients with type 2 diabetes observed for 10 years in primary care practices in Badajoz, Spain.

METHODS

Observational, longitudinal study. A total of 643 patients (mean age 64.0 years, 55.7% women), without evidence of cardiovascular disease were studied. We assessed the incidence of cardiovascular events and the patients' 10-year coronary risk predicted-values at the time of their recruitment.

RESULT

The actual incidence rate of coronary events was 14.5% (15.1% in women and 13.7% in men, p = 0.616). Patients who suffered coronary events were older (66.3 vs 63.6 years, p < 0.05), had higher total cholesterol (236.3 vs 219.5 mg/dl, p < 0.01), fasting plasma glucose levels (177.6 vs 159.8 mg/dl, p < 0.01), glycated haemoglobin (7.3 vs 6.7%, p < 0.05) and also higher prevalence of high blood pressure, dyslipidemia and chronic renal disease. The original Framingham equation overpredicted risk by 88%, whereas the REGICOR Framingham function underpredicted risk by 24%.

CONCLUSIONS

Diabetes in our cohort does not behave as a coronary heart disease equivalent and both the original and REGICOR Framingham coronary risk functions have little utility in a diabetic population.

Comparison of different vascular risk engines in the identification of type 2 diabetes patients with high cardiovascular risk

Background

Some authors consider that secondary prevention should be conducted for all DM2 patients, while others suggest that the drug preventive treatment should start or be increased depending on each patient’s individual CVR, estimated using cardiovascular or coronary risk functions to identify the patients with a higher CVR. The principal objective of this study was to assess three different cardiovascular risk prediction models in type 2 diabetes patients.

Methods

Multicentre, cross-sectional descriptive study of 3,041 patients with type 2 diabetes and no history of cardiovascular disease. The demographic, clinical, analytical, and cardiovascular risk factor variables associated with type 2 diabetes were analysed. The risk function and probability that a cardiovascular disease could occur were estimated using three risk engines: REGICOR, UKPDS and ADVANCE. A patient was considered to have a high cardiovascular risk when REGICOR ≥ 10 % or UKPDS ≥ 15 % in 10 years or when ADVANCE ≥ 8 % in 4 years.

Results

The ADVANCE and UKPDS risk engines identified a higher number of diabetic patients with a high cardiovascular risk (24.2 % and 22.7 %, respectively) compared to the REGICOR risk engine (10.2 %). The correlation using the REGICOR risk engine was low compared to UKPDS and ADVANCE (r = 0.288 and r = 0.153, respectively; p < 0.0001). The agreement values in the allocation of a particular patient to the high risk group was low between the REGICOR engine and the UKPDS and ADVANCE engines (k = 0.205 and k = 0.123, respectively; p < 0.0001) and acceptable between the ADVANCE and UKPDS risk engines (k = 0.608).

Conclusions

There are discrepancies between the general population and the type 2 diabetic patient-specific risk engines. The results of this study indicate the need for a prospective study which validates specific equations for diabetic patients in the Spanish population, as well as research on new models for cardiovascular risk prediction in these patients.

External validation of the UKPDS risk engine in incident type 2 diabetes: a need for new type 2 diabetes-specific risk equations

OBJECTIVE

To evaluate the performance of the UK Prospective Diabetes Study Risk Engine (UKPDS-RE) for predicting the 10-year risk of cardiovascular disease end points in an independent cohort of U.K. patients newly diagnosed with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This was a retrospective cohort study using routine health care data collected between April 1998 and October 2011 from ∼350 U.K. primary care practices contributing to the Clinical Practice Research Datalink (CPRD). Participants comprised 79,966 patients aged between 35 and 85 years (388,269 person-years) with 4,984 cardiovascular events. Four outcomes were evaluated: first diagnosis of coronary heart disease (CHD), stroke, fatal CHD, and fatal stroke.

RESULTS

Accounting for censoring, the observed versus predicted 10-year event rates were as follows: CHD 6.1 vs. 16.5%, fatal CHD 1.9 vs. 10.1%, stroke 7.0 vs. 10.1%, and fatal stroke 1.7 vs. 1.6%, respectively. The UKPDS-RE showed moderate discrimination for all four outcomes, with the concordance index values ranging from 0.65 to 0.78.

CONCLUSIONS

The UKPDS stroke equations showed calibration ranging from poor to moderate; however, the CHD equations showed poor calibration and considerably overestimated CHD risk. There is a need for revised risk equations in type 2 diabetes.

Assessing Framingham cardiovascular risk scores in subjects with diabetes and their correlation with diabetic retinopathy

Aim:

To study the Framingham cardiovascular risk assessment scores in subjects with diabetes and their association with diabetic retinopathy in subjects with diabetes.

Materials and Methods:

In this population-based prospective study, subjects with diabetes were recruited (n=1248; age ≥40 years). The Framingham cardiovascular risk scores were calculated for 1248 subjects with type 2 diabetes. The scores were classified as high risk (>10%), and low risk (<10%).

Results:

Out of the 1248 subjects, 830 (66.5%) patients had a low risk of developing cardiovascular disease (CVD) in 10 years and 418 (33.5%) had a high risk of developing CVD in 10 years. The risk of developing CVD was more in males than females (56.8% vs. 7%) The prevalence of both diabetic retinopathy and sight-threatening retinopathy was more in the high-risk group (21% and 4.5%, respectively). The risk factors for developing diabetic retinopathy were similar in both the groups (low vs. high) – duration of diabetes (OR 1.14 vs. 1.08), higher HbA1c (OR 1.24 vs. 1.22), presence of macro- and microalbuminuria (OR 10.17 vs. 6.12 for macro-albuminuria) and use of insulin (OR 2.06 vs. 4.38). The additional risk factors in the high-risk group were presence of anemia (OR 2.65) and higher serum high density lipoprotein (HDL) cholesterol (OR 1.05).

Conclusion:

Framingham risk scoring, a global risk assessment tool to predict the 10-year risk of developing CVD, can also predict the occurrence and type of diabetic retinopathy. Those patients with high CVD scores should be followed up more frequently and treated adequately. This also warrants good interaction between the treating physician/cardiologist and the ophthalmologist.

Risco cardiovascular, efetividade e mortalidade

A Lei de Ferro da Epidemiologia (Ley de Hierro de La Epidemiología) diz que todos que nascem, morrem. Por isso, o propósito da Medicina não é evitar a morte por si só, mas evitar as mortes, as doenças e o sofrimento que podem ser medicamente evitáveis.No final, todos nossos pacientes morrerão – e nós também, obviamente, morreremos. “Os corpos encontram uma forma de morrer”, e se a causa não for por fome ou desidratação, por motivo congênito e infeccioso, por lesões, câncer ou suicídio, temos que esperar que seja por ‘motivo cardiovascular’, doença pulmonar, insuficiência renal ou hepática, demência ou outras doenças degenerativas. Mas temos que morrer por alguma coisa.Morrer por causa cardiovascular não é desonroso, nem refere-se à atenção clínica imperfeita. O fato de a primeira causa de morte ser a cardiovascular não tem nenhuma relação com os cuidados clínicos e nem deveria assustar.Entretanto, muitas das mortes por motivo cardiovascular poderiam ser evitadas. Assim, poder-se-ia evitar mortalidade cardiovascular, diminuindo a desigualdade social, por exemplo, com melhor redistribuição da riqueza, melhor educação etc. Os médicos sabem que os fatores adversos psicossociais associados ao fato de pertencer à classe baixa correspondem a 35% do risco atribuído à hipertensão na incidência do infarto do miocárdio (em outra hipótese, pertencer à classe baixa duplica 2,7 tal risco)1.Também deve-se saber que, contra as mortes cardiovasculares, não há nada como as políticas de saúde pública quanto ao tabagismo (restrições dos lugares onde fumar, aumento do preço do tabaco, campanhas de informação, entre outras).Na parte clínica, as mortes cardiovasculares evitáveis devem ser vistas em perspectiva, de acordo com o que seja possível conseguir2. Portanto, por 100.000 habitantes ao ano, o tratamento com inibidores da enzima conversora de angiotensina (IECA) na insuficiência cardíaca pode evitar 308 mortes; o breve conselho médico contra o tabaco, 120; o tratamento da hipertensão, 71; o uso de aspirina para o infarto do miocárdio, 48; o tratamento anticoagulante na fibrilação auricular, 33; o uso das estatinas para o infarto do miocárdio (prevenção secundária), 14; e o tratamento com estatinas nos pacientes com risco cardiovascular (prevenção primária), 3 mortes. Por isso, o uso das estatinas para prevenir mortes cardiovasculares em pacientes sem doenças coronárias é muito ineficiente.O risco cardiovascular é calculado seguindo tabelas adequadas. A mais conhecida é a de Framingham. Essa tabela foi obtida com dados de uma população anglo-saxã, que forneceram resultados muito diferentes de outras populações, como as mediterrâneas em que se aplica com melhor validade científica a tabela REGICOR3. Talvez, a tabela de Framingham também seria inapropriada para a população brasileira. Em todo caso, as tabelas de risco cardiovascular são aplicáveis às populações, não aos sujeitos.As tabelas de risco não são tabelas de decisão. Ou seja, não permitem tomar decisões na consulta com o paciente. Transformam-se em tabelas de decisão por meio da análise do impacto, que não foi feita com as tabelas de risco cardiovascular4.Portanto, passar da população (tabela de risco) ao paciente na consulta é uma tragédia ‘clínica-estatística’5.Assim, se os pacientes forem acompanhados por dez anos, a incidência dos infartos do miocárdio será muito menor do que a esperada nos pacientes classificados como de alto risco (e será muito maior do que a prevista nos de ‘baixo risco’)6.Há um excesso, muito risco cardiovascular na mesma proporção das mortes cardiovasculares7. As tabelas de risco são inúteis e perigosas para se aplicar a um paciente individualmente4,8.As tabelas de risco cardiovascular deveriam ser retiradas da consulta ao médico para proteger o paciente dos excessos no diagnóstico e no tratamento.Os médicos podem se confundir ao atribuírem aos fatores de risco um componente causal. Os fatores de risco não são causa, mas sim associações estatísticas. Os fatores de risco não são nem causa, nem são necessários ou suficientes9.As estatísticas do fator de risco nos pacientes dizem pouco a respeito do problema da mortalidade cardiovascular na população. É mais conveniente observar as estatísticas na perspectiva e não empregá-las para justificar o uso inadequado das estatinas e de outras terapêuticas. Os fatores de risco podem levar à confusão10.A prevenção primária cardiovascular com estatinas não tem fundamento científico11.Lamentavelmente, os médicos empregam as estatinas em excesso para a prevenção primária – na qual são inúteis e perigosas – e pouco na prevenção secundária – quando há isquemia coronária, sendo úteis e necessárias12,13.O mais lógico seria se concentrar na prevenção secundária como clínicos e deixar a prevenção primária cardiovascular para o trabalho conjunto dos médicos gerais/de família com a saúde pública (saúde coletiva), por exemplo, contra o tabagismo, oferecendo o melhor de ambos os mundos para a sociedade.

Incidence of complications and mortality in a type 2 diabetes patient cohort study followed up from diagnosis in a primary healthcare centre

AIMS

To determine the microvascular and macrovascular complications and mortality incidence rates and to identify the related factors in patients recently diagnosed with type 2 diabetes between 1991 and 2000 and followed until 2006.

METHODS

Retrospective longitudinal study in a primary healthcare center. Patients without any measure of glycaemia in the 3 years previous to diabetes diagnosis were excluded. Annual incidence rates for microvascular and macrovascular complications and mortality were estimated. Analysis of KaplanMeier survival curves and Cox proportional risk models by gender were done.

RESULTS

Of 469 patients [mean age: 60.4 (SD 10.7) years, 53.9% women], 80 died principally of tumoral (38.7%) and cardiovascular (30%) causes. The mean follow-up period was 8.81 years. (SD 3.21). The complication rates per 1000 patients/year (95% CI) were: microvascular complications 29.11 (22.97-36.38), macrovascular complications 24.10 (19.05-30.08) and mortality 19.23 (15.25-23.93), all of those being significantly greater in males except for cerebrovascular disease. Complications and mortality were associated with age, HbA1c, HDL-cholesterol, blood pressure and smoking with a different significance for each gender. HbA1c was related to microvascular complications in both sexes and to macrovascular complications only in women.

CONCLUSION

The annual rates for death and complications in a Mediterranean type 2 diabetic patient cohort followed from diagnosis were lower than those published in Anglo-Saxon countries. Males showed higher death and complication rates except in terms of cerebrovascular disease. Predictors of complication and death were different depending on gender. In terms of mortality, unlike in other studies, only one-third of the deaths were for cardiovascular causes.

Cardiovascular risk assessment scores for people with diabetes: a systematic review

People with type 2 diabetes have an increased risk of cardiovascular disease (CVD). Multivariate cardiovascular risk scores have been used in many countries to identify individuals who are at high risk of CVD. These risk scores include those originally developed in individuals with diabetes and those developed in a general population. This article reviews the published evidence for the performance of CVD risk scores in diabetic patients by: (1) examining the overall rationale for using risk scores; (2) systematically reviewing the literature on available scores; and (3) exploring methodological issues surrounding the development, validation and comparison of risk scores. The predictive performance of cardiovascular risk scores varies substantially between different populations. There is little evidence to suggest that risk scores developed in individuals with diabetes estimate cardiovascular risk more accurately than those developed in the general population. The inconsistency in the methods used in evaluation studies makes it difficult to compare and summarise the predictive ability of risk scores. Overall, CVD risk scores rank individuals reasonably accurately and are therefore useful in the management of diabetes with regard to targeting therapy to patients at highest risk. However, due to the uncertainty in estimation of true risk, care is needed when using scores to communicate absolute CVD risk to individuals.

Family physician and endocrinologist coordination as the basis for diabetes care in clinical practice

BACKGROUND

To estimate the proportion of diabetic patients (DPts) with peripheral vascular disease treated at a primary health care site after an endocrinologist-based intervention, who meet ATP III and Steno targets of metabolic control, as well as to compare the outcome with the results of the patients treated by endocrinologists.

METHODS

A controlled, prospective over 30-months period study was conducted in area 7 of Madrid. One hundred twenty six eligible diabetic patients diagnosed as having peripheral vascular disease between January 2003 and June 2004 were included in the study. After a treatment period of three months by the Diabetes team at St Carlos Hospital, 63 patients were randomly assigned to continue their follow up by diabetes team (Group A) and other 63 to be treated by the family physicians (FP) at primary care level with continuous diabetes team coordination (Group B). 57 DPts from Group A and 59 from Group B, completed the 30 months follow-up period. At baseline both groups were similar in age, weight, time from diagnosis and metabolic control. The main outcomes of this study were the proportion of patients meeting ATP III and Steno goals for HbA1c (%), Cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, blood pressure, albumine-to-creatinine excretion ratio (ACR), body mass index (BMI), waist circumference (WC), anti-aggregation treatment and smoking status.

RESULTS

At the end of the follow up, no differences were found between the groups. More than 37% of diabetic patients assigned to be treated by FP achieved a HbA1c < 6.5%, more than 50% a ACR < 30 mg/g, and more than 80% reached low risk values for cholesterol, LDL cholesterol, triglycerides, diastolic blood pressure and were anti-aggregated, and 12% remained smokers. In contrast, less than 45% achieved a systolic blood pressure < 130 mm Hg, less than 12% had a BMI < 25 Kg.m-2 (versus 23% in group A; p < 0.05) and 49%/30% (men/women) had a waist circumference of low risk.

CONCLUSION

Improvements in metabolic control among diabetic patients with peripheral vascular disease treated at a primary health care setting is possible, reaching similar results to the patients treated at a specialized level. Despite such an improvement, body weight control remains more than poor in both levels, mainly at primary care level. General practitioner and endocrinologist coordination care may be important to enhance diabetes management in primary care settings.

TRIAL REGISTRATION

Clinical Trial number ISRCTN75037597.

[Limits to the power of medicine to define disease and risk factor, and quarternary prevention]

Patient safety means to avoid unnecessary harm produces by health care activities. Quaternary prevention is a medical activity that try to avoid or decrease the health consequences of unnecessary or excesive health care. Physicians' definition of health, risk factor and disease justify many unnecessary medical interventions. It is critical to control an excesive medical technological actitude that allows excesive medical interventions. The medical power of definition of health and disease transform risk factor in a border which usually overlap with the disease field. We need research on quaternary prevention, and to develop activities of quaternary prevention which help in stopping the dissemination of health care (preventive, curative, diagnostic or therapeutic) of little value.

Cardiovascular disease risk in subjects with type 2 diabetes mellitus in a population in southern Spain

To calculate overall 10-year cardiovascular disease (CVD) risk for patients with type 2 diabetes we applied the UKPDS and SCORE prediction models to data derived from clinical notes of 1846 patients (mean age 65.5 years; 55.8% women) with type 2 diabetes attending eight Primary-Care Centres serving a catchment population of 200,000 citizens in Andalusia. The results showed obesity and high blood pressure present in >50%, established CVD in 24%, retinopathy in 30%, and nephropathy in 17%. Mean HbAlc level was 7.3%. Compliance with therapeutic goals was 54% for systolic blood pressure <130 mmHg, 39% for HbA1c <7% and 9% for LDL cholesterol <2.58 mmol/L. Approximately 33% were receiving treatment with metformin, statins, renin-angiotensin system inhibitors and anti-aggregation agents. UKPDS risk for coronary heart disease (CHD) was 23% and 16% for stroke. The SCORE 10-year mortality risk was 5%. Correlation coefficient between the two models predicting CVD risk was 0.68 (p<0.001). We conclude that, despite the European consensus that CVD is low in Mediterranean countries, the CVD risk factors in the type 2 diabetes sub-population in southern Spain is relatively high. Specific measures of health-care intervention are needed if CVD-associated morbido-mortality rates in these diabetic patients are to be reduced.

Prediction of first coronary events with the Framingham score: a systematic review

BACKGROUND

Uncertainty exists about the performance of the Framingham risk score when applied in different populations.

OBJECTIVE

We assessed calibration of the Framingham risk score (ie, relationship between predicted and observed coronary event rates) in US and non-US populations free of cardiovascular disease.

METHODS

We reviewed studies that evaluated the performance of the Framingham risk score to predict first coronary events in a validation cohort, as identified by Medline, EMBASE, BIOSIS, and Cochrane library searches (through August 2005). Two reviewers independently assessed 1496 studies for eligibility, extracted data, and performed quality assessment using predefined forms.

RESULTS

We included 25 validation cohorts of different population groups (n = 128,000) in our main analysis. Calibration varied over a wide range from under- to overprediction of absolute risk by factors of 0.57 to 2.7. Risk prediction for 7 cohorts (n = 18658) from the United States, Australia, and New Zealand was well calibrated (corresponding figures: 0.87-1.08; for the 5 biggest cohorts). The estimated population risks for first coronary events were strongly associated (goodness of fit: R2 = 0.84) and in good agreement with observed risks (coefficient for predicted risk: beta = 0.84; 95% CI 0.41-1.26). In 18 European cohorts (n = 109499), the corresponding figures indicated close association (R2 = 0.72) but substantial overprediction (beta = 0.58, 95% CI 0.39-0.77). The risk score was well calibrated on the intercept for both population clusters.

CONCLUSION

The Framingham score is well calibrated to predict first coronary events in populations from the United States, Australia, and New Zealand. Overestimation of absolute risk in European cohorts requires recalibration procedures.

[Validation of 3 equations of coronary risk in diabetic population of a primary care center]

BACKGROUND AND OBJECTIVE

We intended to validate to 10 years 3 equations of coronary risk that use the function of original Framingham (Framingham-Anderson and Framingham-Wilson) and calibrated for Spanish population (Framingham-REGICOR) in diabetic patients type 2.

PATIENTS AND METHOD

We included a total of 190 diabetic patients from a primary care center, without coronary heart disease, in whom the coronary risk could be calculated before 1 January 1995. All were followed during 10 years.

RESULTS

The highest score of cardiovascular risk was obtained in the Framingham-Wilson function chart (25.4%) and the lowest in the Framingham-REGICOR (10.8%). The real incidence of coronary events was 14.7% (p < 0.001). Statistically significant differences between patients with or without coronary events were only observed in the Framingham-REGICOR equation (13.3% vs 10.3%; p = 0.046). Framingham-Anderson and Framingham-Wilson functions charts more than doubled the risk of coronary disease in men (p < 0.001). The agreement degree between the 3 functions was acceptable except for the calculation of coronary risk in men between Framingham-REGICOR and Framingham-Wilson equations (kappa index = 0.3). Framingham-Anderson and Framingham-Wilson functions charts showed similar profiles for the patients with high coronary risk. Sensitivity was superior in Framingham-Anderson and Framingham-Wilson functions (67.8%) and specificity was optimal in Framingham-REGICOR equation (51.2%). The positives predictive values were low and the negatives predictive values were high.

CONCLUSIONS

The equations of Framingham-Wilson and Framingham-Anderson overestimate the coronary risk in diabetics, whereas the Framingham-REGICOR functions underestimates it. The utility of these 3 methods is reduced in the diabetic population.