Toward evidence-based diagnosis in developing countries: the use of likelihood ratios for robust quick diagnosis

Evidence-based medicine [EBM], a relatively new paradigm for clinical practice, stresses the use of research evidence in diagnostic evaluations and therapeutic interventions. Financial and instrumental scarcities in developing countries require clinicians to visit patients under time constraints, especially in outpatient clinical settings. In this situation, clinicians need diagnostic approaches that reduce both diagnostic time and errors. This article discusses what EBM can do to help physicians in this regard. For quick history taking and physical examination, all physicians utilize certain [key pointers] [signs or symptoms or paraclinical tests that influence the pretest estimation of the disease prevalence]. EBM emphasizes that these key pointers are nothing but signs or symptoms with significant likelihood ratios. Likelihood ratios are a practical means of interpreting clinical tests; physicians can derive likelihood ratios from critically appraised studies. The use of clinical tests with sizeable likelihood ratios and with likelihood ratios for key pointers from independent body systems may significantly decrease both diagnostic time and errors. EBM could be a significant aid to physicians in the developing world

relationship between leptin and insulin resistance in Iranian obese children

Leptin is an adipocyte- derived hormone that plays an important role in the pathogenesis of obesity. Obesity is associated with insulin resistance and hyperinsulinemia. Insulin resistance is one of the factors which have been suggested to affect leptin serum levels. There are few studies evaluating the relation between leptin level and insulin resistance in childhood and adolescence obesity. The aim of the present study is to investigate this relationship in Iranian obese children. We screened 13089 primary school students aged 7-12 years. Children were divided to overweight and normal based on the recently published National Center for Health Statistics growth charts. The number of children which were overweight was 498, of whom 347 subjects particiated in the study. Fasting blood glucose, insulin and leptin levels were measured and homeostasis model assessment [HOMA] of insulin resistance [HOMA-IR] and fasting glucose to insulin ratio [FGIR] were calculated and compared between two groups. Serum leptin levels were significantly higher in overweight compared to normal group. [11.58 +/- 8.1 and 8.1 +/- 5.2 respectively p<0.05]. Before adjustment for BMI, there was a significant correlation between leptin and fasting insulin, HOMA -IR index and FGIR. [r=0.1, p< 0.05, r=0.1, p<0.01, r=0.07, p<0.05 respectively]. After adjustment for BMI, no significant correlation was found [r=0.097, p=0.20]. The relation between leptin and insulin resistance was weak and disappeared after adjustment for BMI. It seems that many other factors including BMI and total fat amount may affect this relationship. Further studies in this field are required