PHILADELPHIA – Prednisone appears to have the edge over colchicine for control of pain in patients with acute calcium pyrophosphate (CPP) crystal arthritis, an intensely painful rheumatic disease primarily affecting older patients.
Among 111 patients with acute CPP crystal arthritis randomized to receive either prednisone or colchicine for control of acute pain in a multicenter study, 2 days of therapy with the oral agents provided equivalent pain relief on the second day, and patients generally tolerated each agent well, reported Tristan Pascart, MD, from the Groupement Hospitalier de l’Institut Catholique de Lille (France).
Neil Osterweil/MDedge News
Dr. Tristan Pascart
“Almost three-fourths of patients are considered to be good responders to both drugs on day 3, and, maybe, safety is the key issue distinguishing the two treatments: Colchicine was generally well tolerated, but even with this very short time frame of treatment, one patient out of five had diarrhea, which is more of a concern in this elderly population at risk of dehydration,” he said in an oral abstract session at the annual meeting of the American College of Rheumatology.
In contrast, only about 6% of patients assigned to prednisone had diarrhea, and other adverse events that occurred more frequently with the corticosteroid, including hypertension, hyperglycemia, and insomnia all resolved after the therapy was stopped.
Common and acutely painful
Acute CPP crystal arthritis is a common complication that often occurs during hospitalization for primarily nonrheumatologic causes, Dr. Pascart said, and “in the absence of clinical trials, the management relies on expert opinion, which stems from extrapolated data from gap studies” primarily with prednisone or colchicine, Dr. Pascart said.
To fill in the knowledge gap, Dr. Pascart and colleagues conducted the COLCHICORT study to evaluate whether the two drugs were comparable in efficacy and safety for control of acute pain in a vulnerable population.
The multicenter, open-label trial included patients older than age 65 years with an estimated glomerular filtration rate above 30 mL/min per 1.73 m2 who presented with acute CPP deposition arthritis with symptoms occurring within the previous 36 hours. CPP arthritis was defined by the identification of CPP crystals on synovial fluid analysis or typical clinical presentation with evidence of chondrocalcinosis on x-rays or ultrasound.
Patients with a history of gout, cognitive decline that could impair pain assessment, or contraindications to either of the study drugs were excluded.
The participants were randomized to receive either colchicine 1.5 mg (1 mg to start, then 0.5 mg one hour later) at baseline and then 1 mg on day 1, or oral prednisone 30 mg at baseline and on day 1. The patients also received 1 g of systemic acetaminophen, and three 50-mg doses of tramadol during the first 24 hours.
Of the 111 patients randomized, 54 were assigned to receive prednisone, and 57 were assigned to receive colchicine. Baseline characteristics were similar between the groups, with a mean age of about 86 years, body mass index of around 25 kg/m2, and blood pressure in the range of 130/69 mm Hg.
For nearly half of all patients in study each arm the most painful joint was the knee, followed by wrists and ankles.
There was no difference between the groups in the primary efficacy outcome of a change at 24 hours over baseline in visual analog scale (VAS) (0-100 mm) scores, either in a per-protocol analysis or modified intention-to-treat analysis. The mean change in VAS at 24 hours in the colchicine group was –36.6 mm, compared with –37.7 mm in the prednisone group. The investigators had previously determined that any difference between the two drugs of less than 13 mm on pain VAS at 24 hours would meet the definition for equivalent efficacy.
In both groups, a majority of patients had either an improvement greater than 50% in pain VAS scores and/or a pain VAS score less than 40 mm at both 24 and 48 hours.
At 7 days of follow-up, 21.8% of patients assigned to colchicine had diarrhea, compared with 5.6% of those assigned to prednisone. Adverse events occurring more frequently with prednisone included hyperglycemia, hypertension, and insomnia.
Patients who received colchicine and were also on statins had a trend toward a higher risk for diarrhea, but the study was not adequately powered to detect an association, and the trend was not statistically significant, Dr. Pascart said.
“Taken together, safety issues suggest that prednisone should be considered as the first-line therapy in acute CPP crystal arthritis. Future research is warranted to determine factors increasing the risk of colchicine-induced diarrhea,” he concluded.