The impact of frailty at diagnosis on mortality and hospital admissions in secondary spontaneous pneumothorax using the SAIL Databank: a study protocol.

Abstract Background The prevalence of frailty is increasing as the global population ages. The relationship between frailty and poor outcomes and the utility of frailty indices to assess frailty is well documented. Although secondary spontaneous pneumothorax (SSP) is common, there are no data evaluating the relationship between frailty and outcomes in this condition. This protocol describes an observational study assessing the correlation between frailty and mortality, amongst other clinical outcomes, in patients with SSP.Methods We will use ICD-10 and NHS read codes to identify participants with a first episode of SSP after 1st January 2005 from the SAIL Databank. The participants will be stratified by frailty status using the electronic frailty index (eFI) measured at or near to the time of diagnosis. Baseline data, including patient demographics, comorbidities, smoking status and date of death, will be collected. The eFI will be correlated with clinical outcomes including mortality, time to hospitalisation, length of stay and readmissions. Our primary analysis will be all-cause mortality by eFI, adjusted for age, sex, deprivation, smoking status and comorbidities. The secondary analyses will be disease-specific mortality, time to first hospital admission, length of stay, and readmissions. All analyses will be presented as crude and adjusted HR and OR with associated 95% CIs and p values.Discussion This study will be the first to explore the association between frailty and clinical outcomes in SSP. The eFI has the potential to be used to predict outcomes and guide clinical decision making for complex, multimorbid patients with SSP.