The inverse equity hypothesis in the implementation of NASF-AB in municipalities of Southern Brazil.

The present study aimed to analyze the evolution of the implementation of Family Health and Primary Health Care Expanded Support Centers (NASF-AB, in Portuguese) in the municipalities of Southern Brazil, from 2008 to 2019, in light of the inverse equity hypothesis. This was an ecological study, considering 1,188 municipalities of Southern Brazil. The analyses were separated by state, with municipalities divided into quartiles of Municipal Human Development Index - Income (MHDI-Income). Our study calculated the cumulative percentage of the implementation of NASF-AB within the given period and the inequality between Q1 (richest) and Q4 (poorest), assessed by the absolute and relative inequality measures. In Paraná, Q1 presented a higher coverage of NASF-AB than did Q4, and, although the inequality had decreased at the end of the period, it was still quite distinct, according to the "top inequality" pattern. In Santa Catarina, the predictions of the hypothesis were confirmed, with inequalities found in the beginning of the period and a near 90% decline once NASF-AB had been implemented in the municipalities of Q1, characterizing the "bottom inequality" pattern. In Rio Grande do Sul, the hypothesis was refuted observing that since 2014 there was a greater implementation in Q4 as compared to Q1 was observed.