Validation of the Swedevox registry of continuous positive airway pressure, long-term mechanical ventilator and long-term oxygen therapy

Background The Swedish Registry of Respiratory Failure (Swedevox) collects nationwide data on patients starting continuous positive airway pressure (CPAP) treatment, long-term mechanical ventilator (LTMV) and long-term oxygen therapy (LTOT). We validated key information in Swedevox against source data from medical records. Methods This was a retrospective validation study of patients starting CPAP (n=175), LTMV (n=177) or LTOT (n=175) across seven centres 2013–2017. Agreement with medical record data was analysed using differences in means (sd) and proportion (%) of a selection of clinically relevant variables. Variables of interest included for CPAP: apnoea–hypopnoea index (AHI), height, weight, body mass index (BMI) and Epworth Sleepiness Scale (ESS) score; for LTMV: date of blood gas, arterial carbon dioxide tension (PaCO2) (breathing air), weight and diagnosis group; and for LTOT: blood gases breathing air and oxygen, spirometry and main diagnosis. Results Data on CPAP and LTOT had very high validity across all evaluated variables (all 0.5 kPa in 25.9%), weight (>5 kg in 47.5%) and diagnosis group. Inconsistency was higher for patients starting LTMV acutely versus electively (PaCO2 difference >0.5 kPa in 36% versus 21%, p