Psychometric qualities of the 9-item patient-doctor relationship questionnaire in stable Nigerian patients with schizophrenia
Olutayo Aloba, Olufemi Esan, Taiwo Alimi
Background: The patient-doctor relationship concept has not been investigated among Nigerian patients with schizophrenia. The aim of this study was to explore the psychometric qualities of the 9-item Patient-Doctor Relationship Questionnaire (PDRQ-9) in a sample of outpatients receiving treatment for schizophrenia in Southwestern Nigeria. Methods: The PDRQ-9 in addition to other measures was completed by 309 consecutively recruited outpatients receiving treatment for schizophrenia between October 2014 and March 2015. Exploratory and Confirmatory Factor Analyses were used to examine the factorial structure while the reliability and validity were examined using correlational analyses. Results: Exploratory factor analysis confirmed the onedimensionality of the factor structure of the PDRQ-9. The one factor model of the PDRQ-9 had satisfactory goodness of fit (GFI) indices on Confirmatory Factor Analysis (CMIN/DF = 1.72; P = 0.030; GFI = 0.98; adjusted GFI = 0.95; comparative fit index = 0.99; Tucker-Lewis index = 0.98; standardized root mean square residual = 0.021; expected cross-validation index = 0.276; root mean square error of approximation = 0.048). Internal consistency of the scale was satisfactory (Cronbach’s alpha = 0.92). Test-retest reliability was also satisfactory (Intra-class correlation coefficient of 0.738, 95% confidence interval = 0.654-0.802, rp = 0.74, P < 0.001). Construct validity was supported by modest positive correlations with the Trust in physician scale (rp = 0.413, P < 0.001), duration of treatment (rp = 0.114, P = 0.044), number of previous hospitalizations (rp = 0.179, P = 0.002), and negative correlation with the Morisky Adherence Scale (rp = 0.174, P = 0.002). Conclusion: The scale appears useful in the evaluation of the relationship between Nigerian patients with schizophrenia and their psychiatrists. More studies are needed to further explore the properties of this scale among other Nigerian patient population in order to identify other variables that are influencing the patientdoctor relationship.