Geospatial Investigations in Colombia Reveal Variations in the Distribution of Mood and Psychotic Disorders

Background Geographical variations in mood and psychotic disorders have been found in upper-income countries. We investigated geographic variation in these disorders in Colombia, a middle-income country, by analyzing electronic health records (EHRs) from the Clínica San Juan de Dios Manizales (CSJDM), which provides comprehensive mental healthcare for the one million inhabitants of Caldas. Methods We constructed a friction surface map of Caldas and used it to calculate travel-time to CSJDM for 16,295 patients with an initial diagnosis of mood or psychotic disorder. Using a zero-inflated negative binomial regression model, we determined the relationship between travel-time and incidence, stratified by disease severity. We employed spatial scan statistics to look for patient clusters. Results Travel-times (driving) to CSJDM are less than 1 hour for ~50% of the population and more than 4 hours for ~10%. We find a distance-decay relationship for outpatients, but not for inpatients: for every hour increase in travel-time, the number of expected outpatient cases decreases by 20% (RR=0.80, 95% CI [0.71, 0.89], p=5.67E-05). We identify nine clusters/hotspots of inpatients. Conclusions Results reveal inequities in access to healthcare: many individuals requiring only outpatient treatment may live too far from CSJDM to access care. Targeting resources to identify severely ill individuals in hotspots could address treatment inequities and enable studies of factors generating these hotspots.