Validation of Swedevox registry of continuous positive airway pressure (CPAP), long-term mechanical ventilator (LTMV) and long-term oxygen therapy (LTOT)

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 (standard deviation) and proportion (%) of a selection of clinically relevant variables. Variables of interest included for CPAP: Apnea Hypopnea Index (AHI), height, weight, body mass index (BMI) and Epworth Sleepiness Scale (ESS) score; for LTMV: date of blood gas, 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 <5% discrepancy). For LTMV, variability was higher against source information for PaCO₂ (>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 (PaCO_{2 –}difference >0.5 kPa in 36% versus 21%, p<0.05, respectively). However, there were no signs of systematic bias (mean differences close to zero) across the evaluated variables.

Conclusion Validity of Swedevox data, compared with medical records, was very high for CPAP, LTMV and LTOT. The large sample size and lack of systematic differences support that Swedevox data are valid for health care quality assessment and research.