Background: Several asthma patient reported outcome measures (PROMs) have been developed in developed countries. Since social and cultural differences may indirectly influence the PROM therefore, this study has been carried out in Northern Sri Lanka to develop an Asthma Control PROM (AC-PROM) Tamil in the local context.
Methods: The AC-PROM Tamil was developed in 3 steps: item generation, item reduction and psychometric evaluation as guided by the USA Food and Drug Administration. Items were generated through thematic analysis from six focus group discussions among patients with asthma. Items were generated in Tamil and English Languages. A clinician and a clinical pharmacologist refined the items to suit the cultural context. Items were converted to an interviewer administered questionnaire in Tamil in the format of 5–point Likert scale. Item reduction was done by two rounds of online Delphi surveys among 10 experts and an exploratory factor analysis among 200 patients with asthma. Thus developed AC-PROM Tamil was assessed by experts for face and content validity. Criterion validity was evaluated against the forced expiratory volume in one second of 187 patients with asthma. Cut-off value for PROM to assess the asthma control was determined by receiver operating characteristic curve. Reliability was verified by Cronbach’s alpha coefficient.
Results: From thematic analysis of FGD 10 items were generated and these items were refined and subjected to item reduction. During Delphi survey out of 10 items, one was removed. In exploratory factor analysis another one item was removed and remaining 8 items were categorised under 2 factors. Cronbach’s alpha coefficient for AC-PROM Tamil was 0.904, which indicated good reliability. Clarity and relevance of the content of the items were confirmed by the experts. Criterion validity was demonstrated significant correlation between AC-PROM Tamil and forced expiratory volume in one second (r = 0.66, p = 0.001). Cut-off value of AC-PROM Tamil to detect asthma control was 28.5 with sensitivity (79%) and specificity (71%). The AC-PROM Tamil has moderate accuracy (AUC =0.796; 95% CI: 0.73-0.86). Response rate of the AC-PROM Tamil was 100% with no missing data and time taken to complete the PROM was 3-4 minutes.
Conclusion: The AC-PROM Tamil is a simple, reasonably accurate, reliable, objective and valid tool to assess effectiveness of asthma control in Tamil speaking patients during clinical practice and researches.