Smoking increases the risk of diabetic foot amputation: A meta-analysis

Abstract

Accumulating evidence suggests that smoking is associated with diabetic foot amputation. However, the currently available results are inconsistent and controversial. Therefore, the present study performed a meta-analysis to systematically review the association between smoking and diabetic foot amputation and to investigate the risk factors of diabetic foot amputation. Public databases, including PubMed and Embase, were searched prior to 29th February 2016. The heterogeneity was assessed using the Cochran's Q statistic and the I² statistic, and odds ratio (OR) and 95% confidence interval (CI) were calculated and pooled appropriately. Sensitivity analysis was performed to evaluate the stability of the results. In addition, Egger's test was applied to assess any potential publication bias. Based on the research, a total of eight studies, including five cohort studies and three case control studies were included. The data indicated that smoking significantly increased the risk of diabetic foot amputation (OR=1.65; 95% CI, 1.09-2.50; P<0.0001) compared with non-smoking. Sensitivity analysis demonstrated that the pooled analysis did not vary substantially following the exclusion of any one study. Additionally, there was no evidence of publication bias (Egger's test, t=0.1378; P=0.8958). Furthermore, no significant difference was observed between the minor and major amputation groups in patients who smoked (OR=0.79; 95% CI, 0.24-2.58). The results of the present meta-analysis suggested that smoking is a notable risk factor for diabetic foot amputation. Smoking cessation appears to reduce the risk of diabetic foot amputation.

Keywords: diabetic foot; diabetic foot amputation; meta-analysis; smoking.

Figure 1.

Literature search and study selection flow diagram.

Figure 2.

Forest plot of the risk of smoking on diabetic foot amputation. OR, odds ratio; CI, confidence interval; TE, estimated effect; seTE, standard error estimated effect; W, weighted.

Figure 3.

Forest plot of sensitivity analysis. OR, odds ratio; CI, confidence interval.

Figure 4.

Forest plot of the risk of smoking on minor amputation group and major amputation group. OR, odds ratio; CI, confidence interval; TE, estimated effect; seTE, standard error estimated effect; W, weighted.