Rajan et al. applied Markov decision analysis to a clinical scenario in which a 55-year-old patient with Kellgren-Lawrence grade-II or III knee osteoarthritis (OA) undergoes either a series of 3 PRP injections and a 1-year delay to total knee arthroplasty (TKA), or TKA from the outset. Their primary outcome measures were total costs and quality-adjusted life years (QALYs), organized into incremental cost-effectiveness ratios (ICERs). In Markov analyses, if one treatment costs less and produces more QALYs than a comparative treatment, it is considered to be the “dominant” approach.
The authors found that, from a health-care payer perspective, PRP (at an estimated cost of $728 per injection in 2018 US dollars) was not cost-effective if it yielded only a 1-year delay of TKA. However, from a societal perspective (which considered both lost productivity and the need for unpaid caregiving associated with TKA surgery), PRP was cheaper over a lifetime because it delayed direct and indirect costs associated with TKA. The ICER for TKA at the outset was $4,175 per QALY, which is well below the predetermined willingness-to-pay threshold of $50,000. The authors emphasize that this favorable ICER reflects the improved quality of life after TKA compared with published results of PRP injections for knee OA.
Rajan et al. do specify a clinical scenario in which PRP may have a cost-effectiveness advantage over TKA: “…in a higher-risk patient population in whom the perioperative complication rates, TKA revision rate, or postoperative functional outcomes are projected to be worse.”