Global gram-negative diabetic foot infection prevalence and its associations with climate: a systematic review and meta-analysis.

BACKGROUND

The International Working Group on the Diabetic Foot guidelines state that Pseudomonas aeruginosa and overall gram-negative diabetic foot infections (psaDFI and gnDFI) are more common in tropical and subtropical zones vs. temperate zones, and in North Africa/Asia vs. Western Europe/North America based on non-systematic comparisons of cohort studies.

METHODS

We performed a systematic review and meta-analysis of studies of any design and language published between January 1, 2010, and December 15, 2020, that reported the proportion of participants with DFIs and microbiological tests that were positive or negative for Pseudomonas aeruginosa and/or gram-negatives of any species. We calculated the pooled prevalence of psaDFIs and gnDFIs using random effects models.

RESULTS

We identified 246 studies (36,788 participants) reporting on psaDFI prevalence and 55 studies (6,079 participants) reporting on gnDFI prevalence. The psaDFI pooled prevalence in tropical, subtropical, and temperate zones was 19% (95%CI 17-22%), 14% (95%CI 12-17%), and 14% (95%CI 11-17%), respectively. The gnDFI pooled prevalence in tropical, subtropical, and temperate zones was 68% (95%CI 61-74%), 54% (95%CI 45-63%), and 43% (95%CI 35-52%), respectively. The pooled prevalence of psaDFIs and gnDFIs was higher in studies conducted in Asia/North Africa [psaDFI 18% (95%CI 16-20%) and gnDFI 57% (95%CI 51-64%)] compared to studies conducted in North America/Western Europe [psaDFI 12% (95%CI 9-16%) and gnDFI 42% (95%CI 32-52%)]. However, the pooled prevalences of these infections were similar in temperate zones of these regions. Few studies reported data on key risk factors for psaDFIs and gnDFIs, including DFI severity (53%) and prior antibiotic exposure (91%), and there was substantial between-study heterogeneity within climate zones and regions.

CONCLUSIONS

This meta-analysis indicates psaDFIs and gnDFIs may be more prevalent in tropical zones compared to temperate zones and suggests solar climate zones provide additional nuance compared to the guideline-proposed broad regional groupings. However, available studies lack necessary data to separate the effects of climate and location from other risk factors for psaDFIs and gnDFIs. Our findings cannot establish causality between solar climates, regions, and DFI microbiology.

REGISTRATION: PROSPERO CRD42022279019.