Modeling malaria in southernmost provinces of Thailand: A two-step process for analysis of highly right-skewed data with a large proportion of zeros

Abstract

Background Malaria remains a serious health problem in the southern border provinces of Thailand. The issue areas can be identified using an appropriate statistical model. This study aimed to investigate malaria for its spatial occurrence and incidence rate in the southern provinces of Thailand. Methods The Thai Office of Disease Prevention and Control, Ministry of Public Health, provided total hospital admissions of malaria cases from 2008 to 2018, which were classified by age, gender, and sub-district of residence. Twenty-four sub-districts were excluded since they had no malaria cases. A logistic model was utilized to identify spatial occurrence patterns of malaria, and a log-linear regression model was employed to model the incidence rate after eliminating non-cases. Results The overall occurrence rate was 10.9% and the overall median incidence rate was 431 cases per 100,000 population. Malaria occurence peaked at young adults aged 20–29, and subsequently fell with age for both sexes, whereas incidence rate increased with age for both sexes. Malaria occurrence fluctuated, with the largest peak in 2008 and the lowest in 2018, while the incidence rate decreased. The area with the highest malaria occurrence and incidence rate was remarkably similar to the area with the highest number of malaria cases, which were mostly in Yala province's sub-districts bordering Malaysia. Conclusions Malaria is a serious problem in forest-covered border areas. The correct policies and strategies should be concentrated on in these areas, in order to address this condition.