2.2 Outcome and Data Collection
System-reported clinical and administrative data from HVHC’s Unified Data Extract included information about which patients underwent arthroplasty within the grant period. Encounter-level data encompassing demographic information, administrative claims, and health status measures from HVHC system sites between 2012-2015 were integrated with the Unified Data Extract and analyzed. Decision aid exposure was documented in administrative data at the patient level. Patients’ post-decision aid treatment choices were assessed via patient survey data. Patients were asked the following question after viewing decision aids: “At this time, what treatment are you leaning toward for your [hip/knee] pain?” Response categories included [hip/knee] surgery, non-surgical treatment, or not sure.
The patient surveys also captured most patient-level independent variables included in the final analyses – patient sex, age, marital status, race, health insurance, education, HOOS/KOOS pain score, and decision-making stage. The Hip Disability and Osteoarthritis Outcome Score (HOOS) and Knee Disability and Osteoarthritis Outcome Score (KOOS) 10-item and 9-item (respectively) pain subscales were each normalized on a 0-100 scale for analysis (in which 0 indicates no pain and 100 indicates extreme hip or knee pain) and subsequently divided into even terciles corresponding to “low,” “medium,” and “high” categories. The HOOS and KOOS instruments have both been shown to reliably and validly assess short- and long-term pain experienced by patients with osteoarthritis.25,26 To assess decision-making stage, patients were asked the following question after viewing decision aids: “How far along are you with this decision?” Possible responses included the following: [1] “Not yet thought about all of the options,” [2] “Considering the different options,” [3] Close to choosing an option,” and [4] “Already chose an option.” Due to small cell sizes for response [1], responses [1] and [2] were collapsed into a single category to facilitate analysis (renamed “Still considering options” to distinguish it from the original response categories).
The HVHC Unified Data Extract included ICD-9 procedure codes 81.54 (knee arthroplasty) or 81.51 (hip arthroplasty) which were used to classify patients as having received surgery within 6 months of their orthopedic consultations. The Charlson Comorbidity Index (CCI) was also constructed using data drawn from the Unified Data Extract to determine the comorbidity burden of the hip and knee osteoarthritis patients included in the final analytic sample. The CCI is a continuous measure that weights the sum of 17 common comorbid conditions.27