Oral and Poster Presentation ARA-NSW 2021 - 43rd Annual NSW Branch Meeting

Assessing self-reported prescription medication validity in the Australian Rheumatology Association Database (ARAD) using Pharmaceutical Benefits Scheme (PBS) claims data (#12)

Tom Lynch 1 , Premarani Sinnathurai 1 2 , Claire Barrett 3 , Graeme Carroll 4 , Ashley Fletcher 5 6 , Vibhasha Chand 5 6 , Rachelle Buchbinder 5 6 , Catherine Hill 7 , Marissa Lassere 8 , Lyn March 1 2
  1. Institute of Bone and Joint Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
  2. Department of Rheumatology, Royal North Shore Hospital, Sydney, New South Wales, Australia
  3. Redcliffe Hospital, University of Queensland, Brisbane, Queensland, Australia
  4. Department of Rheumatology, Fiona Stanley Hospital, Perth, Western Australia, Australia
  5. Monash Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia
  6. Monash-Cabrini Department of Musculoskeletal Health and Clinical Epidemiology, Cabrini Health, Melbourne, Victoria, Australia
  7. Rheumatology Unit, The Queen Elizabeth Hospital, Adelaide, South Australia, Australia
  8. School of Public Health and Community Medicine, University of New South Wales, Sydney, New South Wales, Australia

Background: Registries and biobanking cohort studies often collect self-reported medication data from participants. The inherent potential for recall bias means validation of self-reports are important for maximising the research utility and accuracy of these data for use in pharmacoepidemiology, health economics and precision medicine outputs.

Methods: We analysed concordance between Australian reference-standard prescription medication dispensing data (Pharmaceutical Benefits Scheme; PBS; 2011-2018), and questionnaire self-reports of current disease-modifying antirheumatic drug (DMARD), corticosteroid, anti-inflammatory and analgesic use from participants in the Australian Rheumatology Association Database (ARAD) cohort (2012-2018). Estimates of sensitivity, positive predictive value (PPV) and inter-rater reliability (Kappa statistic; κ), with 95% confidence intervals (CI) were produced for each medication, matched at the 7-digit Anatomical Therapeutic Chemical (ATC) or PBS item code level, over four fixed time-windows of dispensing data prior to questionnaire completion (30 days, 90 days (Table 1), 6 months and 12 months).

Results: In our study population (n=3282; 67% female; 63.9% rheumatoid arthritis) self-reports of biologic and targeted-synthetic DMARDs with shorter dosing intervals (i.e. daily to 8-weekly) showed very good/excellent agreement in the primary 90-day analysis (ranges: κ 0.85-0.94/PPV 0.83-0.97/sensitivity 0.84-0.96), followed by conventional synthetic DMARDs (κ 0.41-0.86/PPV 0.45-0.86/sensitivity 0.87–1.00), prescription-only non-opioid analgesics (κ 0.65-0.78/PPV 0.6-0.72/sensitivity 0.72-0.86), oral prednisone/prednisolone (κ 0.72/PPV 0.78/sensitivity 0.8) and prescription-only opioid analgesics (κ 0.49-0.7/PPV 0.43-0.71/sensitivity 0.51-0.72).

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Conclusions: Self-reports of prescription-only medications that are dispensed regularly at shorter intervals showed very good/excellent agreement with 90 days of retrospective pharmaceutical claims data. Medications with longer dosing intervals, intermittent use, larger dispensing amounts and/or fractional dosing showed moderate to very good agreement, which improved with wider retrospective time windows of claims data (6 – 12 months). Expectedly, mixed prescription/over the counter medicines were difficult to validate with this method. These results suggest ARAD participants accurately self-report their current rheumatology-related medications via longitudinal patient-reported surveys.