Implantation of Pacemakers in Patients with Chagas disease: A Case-Control Study of Associated Contextual Factors and Prognosis.

Residing in municipalities with larger populations was associated with higher odds of pacemaker implantation in patients with chronic Chagas cardiomyopathy.

• Odds ratio of 3.6 (95% CI: 1.3 to 9.6) for pacemaker implantation among individuals in municipalities with larger populations.
• Study used a nested case-control design within the SaMi-Trop cohort with 46 cases and 138 controls matched 1:3.
• Cases and controls were matched considering equivalence in baseline cardiac severity.
• Binary logistic regression was used to identify independent contextual variables.

Higher coverage of the Family Health Strategy in a municipality was associated with higher odds of pacemaker implantation.

• Odds ratio of 5.3 (95% CI: 1.8 to 15.8) for pacemaker implantation among individuals in municipalities with higher Family Health Strategy coverage.
• This was the strongest contextual predictor of pacemaker implantation among the variables examined.
• Independent variables related to the municipal context were considered in binary logistic regression.

Residing in municipalities with a lower number of electrocardiographs per thousand inhabitants was associated with higher odds of pacemaker implantation.

• Odds ratio of 2.6 (95% CI: 1.0 to 6.6) for pacemaker implantation in municipalities with fewer electrocardiographs per thousand inhabitants.
• This finding suggests that reduced local diagnostic equipment availability paradoxically corresponded with higher pacemaker implantation rates.
• Results were based on a significance level of 5%.

Mortality over 4 years of follow-up was higher among pacemaker-implanted cases than controls, but pacemaker implantation itself did not independently predict death.

• Death was observed in 32.6% of cases (pacemaker recipients) and 21.2% of controls over 4 years of follow-up.
• Cox regression survival analysis adjusted for clinical variables showed pacemaker implantation did not influence mortality.
• Only ejection fraction affected survival, with a relative risk of 7.2 (95% CI: 3.6 to 14.2).
• Cases were patients with CCC who had a pacemaker implanted between waves 1 and 2 of the SaMi-Trop study.

Ejection fraction was the only clinical variable independently associated with survival over the 4-year follow-up period.

• Relative risk of 7.2 (95% CI: 3.6 to 14.2) for death associated with ejection fraction in Cox regression.
• This finding held after adjustment for other clinical variables including pacemaker implantation status.
• The study included 46 cases and 138 controls from the SaMi-Trop cohort.

The study was designed as a nested case-control study within the SaMi-Trop cohort to examine contextual and prognostic factors related to pacemaker implantation in chronic Chagas cardiomyopathy.

• Cases were defined as patients with CCC who had a pacemaker implanted between waves 1 and 2 of the study.
• Controls were matched to cases at a 1:3 ratio considering equivalence in baseline cardiac severity.
• The study included 46 cases and 138 controls.
• Municipal-level contextual variables were used as independent variables, and binary logistic regression was conducted.
• Survival analysis using Cox regression assessed death as the outcome over a 4-year follow-up period.