Abstract
OBJECTIVES: Some patients with obstructive sleep apnea (OSA) do not respond to Continuous Positive Airway Pressure (CPAP) and for these patients, Bi-level PAP is the next level modality. This study by a theory driven hierarchical approach, tries to identify the predictors for CPAP failure among OSA patients. METHODOLOGY: The potential predictors for the model were identified from a theoretical framework rooted in clinical examination, laboratory parameters, and polysomnographic variables pertaining to OSA patients. All patients of OSA who underwent manual titration with CPAP or Bi-level PAP (in case of CPAP Failure) between June 2015 and October 2017 were included in model building. This study compared five competitive models blocks deliberated by increasing order of diagnostic complexity and availability of resources. The fitting of the model was determined by both internal and external validation. RESULTS: Among the five competitive models, the selected model has the significant deviance reduction (-2LL = 121.99, X(2) = 25.55, P < 0.0001) from the baseline model (-2LL = 217.356). This logistic regression model consists of the following binary predictors - Age >60 years (odds ratio [OR] = 3.23 [1.27-8.23]), body mass index >35 Kg/m(2) (OR = 4.25 [1.78-10.13]), forced expiratory volume <60% (OR = 7.33 [2.83-18.72]), apnea-hypopnea index >75 (OR = 4.31 [1.61-11.56]) and T90 > 30% (OR = 6.67 [2.57-17.36]). CONCLUSION: These five factors (acronym as BIPAP) may aid to the clinical decision-making by predicting failure of CPAP and therefore may assist in more vigilant clinical care.