Hospital-Recorded Maintenance Inhaler Coverage, Capsule-Based Dry-Powder Inhaler Technique Errors, and Prior-Year Chronic Obstructive Pulmonary Disease (COPD) Burden in Rural Nepal: A Retrospective Linked-Record Observational Study

BackgroundChronic obstructive pulmonary disease (COPD) remains a substantial clinical burden in Nepal.Effective inhaled maintenance therapy depends on consistent medication availability and correct inhaler technique.This study examined hospital-recorded maintenance inhaler coverage, capsule-based dry-powder inhaler technique errors, and their associations with prior-year COPD-related clinical burden in rural Nepal. Materials and methodsThis retrospective linked-record observational study included 208 adults aged ≥40 years with physicianconfirmed COPD supported by previously documented post-bronchodilator spirometry.Hospital-recorded maintenance inhaler coverage, measured using the proportion of days covered (PDC), and COPD-related clinical outcomes were assessed over the same 365-day period preceding the index visit.Inhaler technique was evaluated once at the index visit using a standardized 10-step observational checklist before corrective retraining.Primary multivariable logistic regression analyses examined associations with frequent exacerbations, emergency department (ED) attendance, and hospitalization.Nested sensitivity analyses among 188 participants with index-date spirometry distinguished the effects of sample restriction from additional adjustment for forced expiratory volume in one second (FEV₁) percent predicted. ResultsMedian hospital-recorded PDC was 76.7% (interquartile range (IQR), 59.2-89.0%),and 94 participants (45.2%) achieved PDC ≥80%.Completely correct inhaler technique was observed in 114 (54.8%) participants, while 50 (24.0%)demonstrated at least one critical technique error.Frequent exacerbations occurred in 78 (37.5%) participants, COPD-related ED attendance in 55 (26.4%), and COPD-related hospitalization in 38 (18.3%).In the primary adjusted analyses, each 10-percentage-point increase in PDC was associated with lower odds of frequent exacerbations (adjusted odds ratio (aOR) 0.77, 95% confidence interval (CI) 0.65-0.92;p = 0.003) and ED attendance (aOR 0.81, 95% CI 0.68-0.97;p = 0.024), but not hospitalization.Critical technique errors were not independently significant in the primary adjusted models.The PDC-ED association was attenuated after restriction to participants with available spirometry (aOR 0.87, 95% CI 0.72-1.05;p = 0.152) and changed minimally after FEV₁ adjustment (aOR 0.88, 95% CI 0.73-1.07;p = 0.195).In spirometry-restricted analyses, critical technique errors were associated with frequent exacerbations, although these exploratory findings differed from the primary full-cohort results. ConclusionsHigher hospital-recorded maintenance inhaler coverage was associated with a lower prior-year frequentexacerbation burden.The association with ED attendance was less consistent across sensitivity analyses, with attenuation occurring after sample restriction rather than additional FEV₁ adjustment.Critical inhalertechnique errors were not independently significant in the primary adjusted models, although associations were observed in restricted-sample analyses.Because medication coverage and clinical outcomes were assessed over the same retrospective period and inhaler technique was measured only at the index visit, temporal and causal relationships cannot be established.Hospital-recorded PDC reflects medication availability rather than confirmed inhaler use.Prospective studies are needed to clarify these associations 1 2 3 4 5