Type 2 Diabetes Mellitus (T2DM) and cardiovascular diseases (CVD) are common in patients with chronic obstructive pulmonary disease (COPD). Prevention of these co-morbidities in COPD requires knowledge on their risk factors. Metabolic syndrome (MetS) predisposes to the development of T2DM and CVD but its prevalence in COPD remains unclear. The aim of this review was to assess the prevalence of MetS and its components in COPD patients compared to controls and to investigate the contribution of clinical characteristics to MetS prevalence. We systematically searched PubMed and EMBASE for original studies in COPD that have investigated the prevalence of MetS and its components. In total, 19 studies involving 4208 COPD patients were included. The pooled MetS prevalence was 34%. Compared to controls, the prevalence was higher in COPD (10 studies, 32% and 30%, p = 0.001). The three most prevalent components in both COPD and controls were arterial hypertension (56% and 51%), abdominal obesity (39% and 38%) and hyperglycemia (44% and 47%). Compared to COPD patients without MetS, those with MetS had higher body mass index (BMI) (29.9 and 24.6 kg/m(2), p < 0.001), higher forced expiratory volume in 1 second (FEV1) % predicted (54 and 51, p < 0.001) and were more frequently female (31% and 25%, p = 0.011). In conclusion, the prevalence of MetS in COPD patients is high and hypertension, abdominal obesity and hyperglycemia are the most prevalent components. Further studies are needed to evaluate the impact of lifestyle factors and medications on MetS in COPD.
Keywords: Co-morbidities; components; lifestyle; prevalence.