Preoperative prescriptions and polypharmacy in elective total hip and knee arthroplasty from 2010 to 2017, a descriptive cohort study.

Background: Evaluation of regular medication is an essential part of the preanesthetic consultation. However, even in elective surgical patients, such as those scheduled for total hip (THA) and knee arthroplasty (TKA), this task may be increasingly complex due to increasing age and number of pharmacologically treated comorbidities. Nevertheless, data on prescribed drugs and polypharmacy in elective surgical patients is sparse.

Methods: Descriptive study in elective unilateral fast-track THA and TKA between 2010 and 2017 based on data from the Centre for fast-track Hip and Knee Replacement Database. Nationwide information on dispensed prescriptions up to 3 months preoperatively was acquired from the Danish National Database of Reimbursed Prescriptions. Drugs were divided into individual subgroups according to the fourth Anatomical Therapeutic Chemical level (ATC4). Primary outcome was changes in the median number of prescribed drugs/year. Secondarily, we investigated the fraction of patients with polypharmacy (≥5 individual ATC4-subgroups), severe polypharmacy (≥10) and specific drugs of relevance at the preanesthetic evaluation.

Results: Of 36,934 procedures in 32,515 patients with a median age of 69 years, we found a median of 3 ATC4-subgroups with no time-related changes regardless of year of surgery but increasing in patients ≥65 years (median: 3 [IQR: 2-4]) versus < 65 years (2 [IQR 1-3]; p < .001). In total, 35.1% and 4.2% had polypharmacy or severe polypharmacy. There was a significant declining trend in severe polypharmacy from 2010 to 2017 (p = .003). Drugs of anesthetic relevance were used by 41.1% of all patients, most often ANG-II or ACE inhibitors and betablockers, which were used by 28.0% and 15.7%. Oral antihyperglycemics was used by 7.8% and 2.0% used insulin. Only 4.0% and 2.1% of patients used vitamin-K antagonists and direct oral anticoagulants, respectively. MAO-inhibitors/Lithium salts were used by 0.3%. The combination of ANG-II/ACE inhibitors, a diuretic and NSAID ("triple whammy") was present in 4.3% of all patients.

Conclusion: Patients scheduled for elective THA and TKA used a median of 3 prescribed drugs. However, 1/3 of patients qualified as having polypharmacy and 41% used drugs requiring anesthetic consideration when planning for surgery.