Aspirin: are patients actually taking it?—A quality assessment study

Abstract

BackgroundThe purpose of the study was to assess patient adherence to an aspirin-based prophylactic deep venous thromboembolism (DVT) care management plan after total lower extremity arthroplasty.MethodsUsing a cross-sectional study design, patients who underwent total hip or knee replacement surgery by a single senior surgeon were surveyed at their routine 6-week follow-up appointment regarding adherence to aspirin DVT prophylaxis. Postoperatively, patients were advised to take 325 mg of aspirin twice daily for 6 weeks to prevent DVT.ResultsOf the 101 patients surveyed, 45 underwent total hip arthroplasty while 56 underwent total knee arthroplasty. There were 48 (48%) patients who were still taking aspirin at their routine 6-week postoperative follow-up appointment and 53 (52%) patients who were not taking aspirin (nonadherent group). Of the latter, 3 (6%) never took aspirin postoperatively, 14 (26%) discontinued within 2 weeks postoperatively, and 23 (43%) did not take it any longer for half the time prescribed. In the nonadherent group, 8 patients reported that they felt they did not need the aspirin prophylaxis, 5 experienced side effects, and 10 were unsure of how long they needed to take it. There was 1 patient with a calf DVT and no episodes of pulmonary embolism.ConclusionsOver half of our study, patients did not finish their aspirin regimen. We suggest a consistent outline of medication duration throughout the pre/postop course and communication regarding aspirin cessation.

Post‐discharge patient‐reported non‐adherence to aspirin compared to enoxaparin for venous thromboembolism prophylaxis after hip or knee arthroplasty

“…13 Our findings regarding reasons for non-adherence are broadly consistent with the few studies that have reported this outcome. 7,10,12 Like other studies, we found that the main reasons were practitionerand education-related rather than being related to drug availability or route of administration. Three recent case series (two for LMWH and one for aspirin) 7,10,12 reported that the most common reasons for non-adherence were forgotten doses, uncertainty of how long to take the medication for, or provider instructions that recommended a change of dose or treatment cessation.…”

“…Non-adherence for injected LMWH as VTE prophylaxis has been reported to range from 10% to 46% 5,7,9,10,15 and from 2% to 52% for oral prophylaxis. 9,10,12,[16][17][18] Based on these figures and on the hypothesis that non-adherence for aspirin would be lower, the sample size calculation used an expected non-adherence of 30% in the enoxaparin group and 15% in the aspirin group, a power of 80% and level of significance of 0.05, yielding a total sample size of 240 patients. Given there were 31 participating hospitals, the aim was to recruit eight patients from each hospital (four from each treatment arm), yielding a total sample of 248.…”

“…5,11 The reasons underlying non-adherence have also been poorly reported, with the exception of one study which found that the most common reasons for non-adherence to extended aspirin prophylaxis were a lack of patient belief that it was required for 6 weeks, uncertainty regarding the required prophylaxis duration and conflicting advice given by practitioners other than the treating surgeon. 12 The CRISTAL trial 13 aimed to determine if aspirin was noninferior to enoxaparin in preventing symptomatic VTE within 90 days following THA or TKA. All patients registered to CRISTAL were asked two adherence related questions at their 90-day follow-up as per the trial protocol.…”

“…Previously published studies have either compared twice‐daily aspirin to LMWH for orthopaedic trauma patients 9,10 or DOACs to LMWH following THA or TKA 5,11 . The reasons underlying non‐adherence have also been poorly reported, with the exception of one study which found that the most common reasons for non‐adherence to extended aspirin prophylaxis were a lack of patient belief that it was required for 6 weeks, uncertainty regarding the required prophylaxis duration and conflicting advice given by practitioners other than the treating surgeon 12 …”

Venous thromboprophylaxis after total hip arthroplasty: aspirin, warfarin, enoxaparin, or factor Xa inhibitors?

“…In addition, the authors also recognise that prescriptions are used as a proxy for anticoagulant use, and we are unable to account for adherence rates. 31 The database used does not offer the patient-level data that would have allowed us to perform a multivariate regression to account for all potential differences in medical comorbidites. Despite this, we were able to match each group by age and sex to find that the CCI for each group was identical.…”