Associations between structures and resources of primary care at the district level and health outcomes: a case study of diabetes mellitus care in Thailand

Background: The structural factors of primary care potentially influence its performance and quality. This study investigated the association between structural factors, including available primary care resources and health outcomes, by using diabetes-related ambulatory care sensitive conditions hospitalizations under the Universal Coverage Scheme in Thailand. Methods: A 2-year panel study used secondary data compiled at the district level. Administrative claim data from 838 districts during the 2014-2015 fiscal years from the National Health Security Office were used to analyze overall diabetes mellitus (DM) hospitalizations and its three subgroups: hospitalizations for uncontrolled diabetes, short-term complications, and long-term complications. Primary care structural data were obtained from the Ministry of Public Health. Generalized estimating equations were used to estimate the influence of structural factors on the age-standardized DM hospitalization ratio. Results: A higher overall DM and uncontrolled diabetes hospitalization ratio was related to an increasing concentration of outpatient utilization (using the Herfindahl-Hirschman Index) (overall DM; beta [standard error, SE]=0.003 [0.001], 95% CI 0.000, 0.006) and decreasing physician density and bed supply (overall DM; beta [SEI1.350 [0.674], 95% CI -2.671, -0.028), beta [SE]=-0.023 [0.011], 95% CI -0.045, -0.001, respectively). Hospitalizations for short-term complications increased with a decrease in health care facility density, whereas hospitalizations for long-term complications increased as that density increased. Rurality was strongly associated with higher hospitalization ratios for all DM hospitalizations except short-term complications. Conclusions: This study identified structural factors associated with health outcomes, many of which can be changed through reorganization at the district level.