Pulmonary function in diabetes: a metaanalysis.

BACKGROUND: Research into the association between diabetes and pulmonary function has resulted in inconsistent outcomes among studies. We performed a meta-analysis to clarify this association. METHODS: From a systematic search of the literature, we included forty studies describing pulmonary function data of 3,182 diabetic patients and 27,080 controls. Associations were summarized pooling the mean difference (MD) (SE) between diabetic patients and controls of all studies for key lung function parameters. RESULTS: For all studies, the pooled MD for FEV(1), FVC and DL(CO) were -5.1 (95% CI, -6.4 to -3.7, P < 0.001), -6.3 (95% CI, -8.0 to -4.7, P < 0.001) and -7.2 (95% CI, -10.0 to -4.4, P < 0.001) %predicted, respectively, and for FEV(1)/FVC 0.1 % (95% CI, -0.8 to 1.0, P = 0.78). Meta-regression analyses showed that between-study heterogeneity was not explained by body mass index, smoking, diabetes duration and glycated hemoglobin (all P > 0.05). CONCLUSION: Diabetes is associated with a modest, albeit statistically significant, impaired pulmonary function in a restrictive pattern. Since our results apply to the diabetic subpopulation free from overt pulmonary diseases, it would next be interesting to investigate the potential clinical implications in those diabetic patients who carry a pulmonary diagnosis, such as chronic obstructive pulmonary disease or asthma.