Introduction: In 2011, the Agence de la santé et des services sociaux de Montréal (ASSSM), in partnership with the region’s Centres de santé et de services sociaux (CSSS), coordinated the implementation of a program on cardiometabolic risk based on the Chronic Care Model. The program, intended for patients suffering from diabetes or hypertension, involved a series of individual follow-up appointments, group classes and exercise sessions. Our study assesses the impact on patient health outcomes of variations in the implementation of some aspects of the program among the six CSSSs taking part in the study. Methods: The evaluation was carried out using a quasi-experimental “before and after” design. Implementation variables were constructed based on data collected during the implementation analysis regarding resources, compliance with the clinical process set out in the regional program, the program experience and internal coordination within the care team. Differences in differences using propensity scores were calculated for HbA1c results, achieving the blood pressure (BP) target, and two lifestyle targets (exercise level and carbohydrate distribution) at the 6- and 12-month follow-ups, based on greater or lesser patient exposure to the implementation of various aspects of the program under study. Results: The results focus on 1185 patients for whom we had data at the 6-month follow- up and the 992 patients from the 12-month follow-up. The difference in differences analysis shows no clear association between the extent of implementation of the various aspects of the program under study and patient health outcomes. Conclusion: The program produces effects on selected health indicators independent of variations in program implementation among the CSSSs taking part in the study. The results suggest that the effects of this type of program are more highly dependent on the delivery of interventions to patients than on the organizational aspects of its implementation.