Asymptomatic falciparum malaria and its effects on type 2 diabetes mellitus patients in Lagos, Nigeria

Abstract

Background: Asymptomatic malaria (ASM) constitutes a reservoir of malaria parasites that sustain transmission and threaten elimination efforts. Studies have also shown a significant relation between insulin resistance and malaria infection. However, data on the clinical effects of ASM and its patterns of carriage among adult malaria patients is limited. Objectives: To determine the prevalence of ASM due to Plasmodium falciparum among adult type 2 diabetes (T2DM) patients in Lagos, Nigeria; to assess the diagnostic performance of light microscopy and histidine-rich protein 2 rapid diagnostic test (HRP-2 RDT); and to determine the effects of ASM on glycemic control and anemia. Materials and Methods: This cross-sectional study enrolled 208 afebrile, nonobese, nonhypertensive T2DM patients, aged 40-70 years, undergoing treatment (adherence, ≥95%) at six private health facilities in Lagos, Nigeria, between March and August 2015. Sociodemographic data were obtained using a semi-structured questionnaire and clinical case files. Venous blood samples were collected and processed for fasting blood sugar estimation, packed cell volume determination and malaria parasite detection by HRP2-RDT, light microscopy and polymerase chain reaction (PCR). Results: The mean age of the patients was 54.5 years. ASM was diagnosed in 16.8%, 7.2% and 4.3% of the patients by PCR, light microscopy and HRP2-RDT, respectively. ASM was significantly (P < 0.05) associated with poor glycemic control, anemia and insulin resistance. The overall parasitemia ranged from 85 to 3789 parasites/μL (median, 1580 parasites/μL). Benchmarking against the PCR results, light microscopy and rapid diagnostic tests were found to have a sensitivity (95% confidence interval) of 42.9% (26.5-59.3) and 22.9% (12.1-39), respectively, in diagnosing ASM. Conclusion: This study revealed that T2DM patients in Lagos, Nigeria, are potential reservoirs of asymptomatic Plasmodium falciparum, which has a significantly negative effect on glycemic control and anemia. The study also found PCR to be the most effective diagnostic method.