Mallinckrodt plc announced two retrospective analyses providing health economic insights on use of Ofirmev for total knee arthroplasty.-

Mallinckrodt plc announced two retrospective analyses that provide health economic insights on use of Ofirmev (acetaminophen) injection – intravenous (IV) acetaminophen – in total knee arthroplasty (TKA) and its impact on length of stay, discharge status and readmissions. Results from these two studies were recently published in the Journal of Knee Surgery. Both retrospective analyses were conducted in the Premier Inc. inpatient hospital database of patients who underwent TKA, and who received either IV or oral acetaminophen from the day of surgery up to day 3 as part of their postoperative pain management, from January 2012 to September 2015. A total of 134,216 patients receiving oral acetaminophen and 56,475 patients receiving IV acetaminophen were included in the two studies.

1. Impact of Intravenous Acetaminophen on Lengths of Stay and Discharge Status after Total Knee Arthroplasty : assessed the postoperative outcomes of TKA patients who received IV acetaminophen versus oral acetaminophen, evaluating the hospital lengths of stay and discharge dispositions. Lengths of stay were calculated as the number of days from the date of hospital admission to the date of discharge, and the discharge disposition was categorized as to home or to a skilled nursing facility (SNF). Key highlights of the analyses, after adjusting for baseline characteristics between treatment groups, include: Compared with the oral group, the IV acetaminophen group had a 0.14-day shorter length of stay (95% confidence interval [CI], –0.15 to –0.13; p < 0.001). Compared with the oral group, the IV group was 22% more likely to be discharged to home (odds ratio [OR] = 1.22; 95% CI, 1.19 to 1.25; p < 0.001). Compared with the oral group, the IV group was 13% less likely to be discharged to a SNF (OR=0.87; 95% CI, 0.85 to 0.90; p < 0.001).

2. Intravenous Acetaminophen May Be Associated with Reduced Odds of 30-Day Readmission after Total Knee Arthroplasty evaluated 30-day hospital readmission rates in TKA patients who received either IV or oral acetaminophen perioperatively and sought to extrapolate the potential annual cost savings on a national level. All causes of readmissions that occurred between patient discharge and 30 days post discharge were recorded. Key highlights include: The readmission rate was 0.04% in the IV and 0.14% in the oral acetaminophen cohorts. After adjusting for baseline characteristics between the treatment groups, IV acetaminophen was associated with a 71% decreased likelihood of readmission within 30 days (OR=0.29; 95% CI, 0.23 to 0.351; p < 0.001) when compared to oral acetaminophen. The reduction in readmissions in the IV acetaminophen group may potentially result in $160 million savings per year on a national level, after accounting for the medication cost.

These two analyses were company-sponsored and conducted in collaboration with researchers primarily from the University of Washington School of Pharmacy, Cleveland Clinic and Joint Replacement Center of Texas. Limitations of these Studies- Data from these studies were obtained from a large observational administrative database, which can be subject to errors in data collection or data entry. Dosage and amount of acetaminophen were recorded from hospital charges instead of what was actually given to the patients. Other adjuvant pain control modalities, such as nerve blocks and wound infiltration, were not assessed or controlled for. However, potential for bias is minimized since these modalities are commonly used with both IV and oral acetaminophen. Like other healthcare databases, the Premier database can only capture patient records after readmission to the same network hospital. Therefore, the true readmission rate might actually be larger.

See- Impact of Intravenous Acetaminophen on Lengths of Stay and Discharge Status after Total Knee Arthroplasty