Long-term mortality in outpatients with type 2 diabetes in a reference hospital in Cameroon: a retrospective cohort study

OBJECTIVES: There are limited data on mortality in patients with type 2 diabetes mellitus (T2DM) in Sub-Saharan Africa. We aimed at determining the mortality rate, and the causes and the predictors of death in patients with T2DM followed as outpatients in a reference hospital in Cameroon. DESIGN: Retrospective cohort study. SETTING: A reference hospital in Cameroon. PARTICIPANTS: From December 2015 to March 2016, patients with T2DM aged 18 years and older and who consulted between January 2009 and December 2014, were contacted directly or through their next of kin, and included in this study. All participants with less than 75% of desired data in files, those who could not be reached on the phone and those who refused to provide consent were excluded from the study. Of the 940 eligible patients, 628 (352 men and 276 women) were included and completed the study, giving a response rate of 66.8%. OUTCOME MEASURES: Death rate, causes of death and predictors of death. RESULTS: Of the 628 patients (mean age: 56.5 years; median diabetes duration: 3.5 years) followed up for a total of 2161 person-years, 54 died, giving a mortality rate of 2.5 per 100 person-years and a cumulative mortality rate of 8.6%. Acute metabolic complications (22.2%), cardiovascular diseases (16.7%), cancers (14.8%), nephropathy (14.8%) and diabetic foot syndrome (13.0%) were the most common causes of death. Advanced age (adjusted HR (aHR) 1.06, 95% CI 1.02 to 1.10; P=0.002), raised glycated haemoglobin (HbA1c) (aHR 1.16, 95% CI 1.00 to 1.35; P=0.051), low blood haemoglobin (aHR 1.06, 95% CI 1.02 to 1.10; P=0.002) and proteinuria (aHR 2.97, 95% CI 1.40 to 6.28; P=0.004) were identified as independent predictors of death. CONCLUSIONS: The mortality rate in patients with T2DM is high in our population, with acute metabolic complications as the leading cause. Patients with advanced age, raised HbA1c, anaemia or proteinuria are at higher risk of death and therefore represent the target of interest to prevent mortality in T2DM.