To describe the results of a Numeric Rating Scale (NRS)-guided pharmacological pain management strategy in symptomatic knee and hip osteoarthritis (OA) in daily clinical practice.
In this observational cohort study, standardised conservative treatment was offered to patients with symptomatic knee and/or hip OA referred to secondary care. Pain management was guided by a NRS for pain, aiming for NRS ≤4. The first step in pharmacological treatment was paracetamol (acetaminophen) in case of no recent use in adequate dose. In case of treatment failure, patients switched to a non-steroidal anti-inflammatory drug (NSAID) and eventually to a second NSAID, each after a 4-week trial period. Predictors for response to treatment were identified. Moreover, reasons for protocol violations were collected.
Three-hundred and forty-seven patients were included. The proportion of patients that reached a response after paracetamol, first and second NSAID was 25% (59/234), 16% (31/190) and 11% (10/87), respectively. Non-adherence to protocol occurred in 46% of cases when switch of analgesic was advised, mainly due to unwillingness of patients to change the analgesic. Identified predictors for response to analgesics included higher age, lower patient global assessment, less stiffness and more radiographic severity.
Adequate use of paracetamol and switching to a NSAID after failing paracetamol resulted in moderate treatment response percentages, whereas the result of a second NSAID was disappointing in patients with advanced knee and hip OA. Predictors for response included patient and disease related factors. A substantial part of patients with NRS >4 were unwilling to change their analgesics.