Seasonal variations in non-traumatic major lower limb amputation in Hong Kong Chinese diabetic patients.

OBJECTIVES To study the relationship between hospitalisation for diabetic foot complications, non-traumatic major lower limb amputations, and seasonal variation in humidity and temperature. DESIGN Retrospective study. SETTING Regional hospital, Hong Kong. PATIENTS Diabetic patients hospitalised for lower limbs infection during the inclusive period 1995 to 2004. MAIN OUTCOME MEASURES Monthly incidence of admissions for diabetic foot sepsis and non-traumatic non-neoplastic major lower limb amputations correlated with the monthly average humidity and temperature. RESULTS During the study period, a total of 770 patients contributed to 1285 episodes of hospitalisation and ensued 208 corresponding major lower limb amputations. Poisson regression study showed that the monthly incidences of hospitalisation as well as amputations were related to the monthly average temperature (P<0.001 and =0.0012, respectively) but not the monthly average humidity (P=0.1560 and 0.6332, respectively). CONCLUSION The warm and humid weather of Hong Kong exerts a seasonal variation on the diabetic foot infection presentations. Warm temperature aggravates the severity of infection and precipitates amputation. More intensive patient education and clustering of medical services in late winter and spring might reduce the incidence of diabetic foot amputation, which is a preventable complication.