Spirometry expert support in family practice: A cluster-randomised trial

Aim: To assess the impact of two modes of spirometry expert support on Family physicians' (FPs') diagnoses and planned management in patients with apparent respiratory disease. Method: A cluster-randomised trial was performed with family practices as the unit of randomisation. FPs from 44 family practices recorded their diagnosis and planned management before and after spirometry for 868 patients. Intervention consisted of spirometry interpretation support by either a chest physician or expert software. Both interventions were compared with usual care (i.e. no additional interpretation support). Change in FPs' diagnoses after spirometry served as the primary outcome. Secondary outcomes were referral rate, additional diagnostic tests, and disease management changes. Effects were expressed as percentages and Odds Ratios (OR) with 95% confidence intervals. Results: Diagnoses changed after intervention in all groups: 47.8% (95% CI 41.8 to 53.9) for chest physician support; 45.0% (95% CI 39.5 to 50.6) for software support; and 53.3% (95% CI 47.2 to 59.4) for usual care. Differences in the proportions of changed diagnosis were not statistically significant: chest physician support versus usual care OR 0.79 (95%CI 0.49 to 1.30); software support versus usual care OR 0.72 (95% CI 0.45 - 1.15). There were no differences in secondary outcomes. Conclusion: Neither chest physician spirometry support nor expert software spirometry support had a significant impact on FPs' diagnosis of respiratory conditions or management decisions.