The individual contribution and relative importance of self-management and quality of care on glycaemic control in Mexican patients with type 2 diabetes

Introduction: The global burden of diabetes can be minimised by interventions focusing on the control of glucose levels. Effective self-management and quality of care have improved diabetes outcomes such as glycaemic levels. However, few studies directly evaluate the relative importance of individual aspects of self-management and quality of care on glycaemic control. Therefore, I evaluated the individual contribution and relative importance of specific aspects of self-management and quality of care on the glycaemic control of Mexican patients with type 2 diabetes.Methods: A longitudinal cohort study was conducted. Consecutive patients were recruited from the waiting rooms in five primary care practices in the city of Aguascalientes, Mexico (from December 2009 to April 2010). These practices are part of the largest social security institution in Mexico (the Mexican Institute for Social Security). Predictors of glycaemic control were measured from medical records and interviews with patients at baseline. Self-management was measured using four questionnaires: the Diabetes Knowledge Questionnaire (DKQ-24), the Medical Prescription Knowledge Questionnaire (MPKQ), the Summary of Diabetes Self-Care Activities (SDSCA), and the Diabetes Self Efficacy Scale. Quality of care was measured using three questionnaires and by extracting data from medical records to evaluate an index of continuity of care (MMCI) and treatment intensification. The questionnaires used were the continuity of care scale from the General Practice Assessment Questionnaire (GPAQ), the Patient? Doctor Communication Scale (PDCS), and the Patient Satisfaction with Diabetes Care scale (PSDC). Glycaemic control (HbA1c levels) was measured at two time points: baseline and six month follow-up. The main analysis was a multivariate regression model with HbA1c at six-month follow-up as the dependent variable and with self-management and quality of care as predictors and demographic and clinical factors as covariates. A secondary analysis considered the interaction between self-management and quality of care in the prediction of HbA1c at six-month follow-up using a multivariate regression model including HbA1c at baseline in the model.Results: The multivariate linear regression model, that included all variables, was significant and explained 36 % of the variance (P <0.01). Patients had lower HbA1c at follow-up if they had lower levels of HbA1c at baseline, received care at one particular practice in the city, had diabetes of shorter duration, and were prescribed monotherapy. When HbA1c at baseline was removed from the model it explained 14% of the variance (P <0.01). Practice and medical prescription remained significant. In addition, lower levels of HbA1c at follow-up were related to the patient undergoing appropriate treatment intensification by their general practitioner. In the secondary analysis, the interaction showed that if treatment was not intensified, good self-managers had lower HbA1c (P <0.01) but if treatment was intensified, the level of self-management had no effect.Conclusions: Treatment intensification was the main predictor of lower HbA1c levels at follow-up. Although none of the self-management predictors was significantly related to HbA1c, an exploratory analysis of self-management/quality of care interactions showed that patients who did not receive treatment intensification but performed more self-management behaviours had lower HbA1c levels at follow-up.