Summary of findings 3. Probenecid compared with allopurinol for chronic gout.
| Probenecid compared with allopurinol for chronic gout | ||||||
| Patient or population: people with chronic gout Settings: Intervention: probenecid Comparison: allopurinol | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Allopurinol | Probenecid | |||||
| Acute gout attacks Follow‐up: median 19.1 months | Study population | RR 0.96 (0.53 to 1.75) | 37 (1 study) | ⊕⊕⊝⊝ low1,2 | Absolute risk difference: 2% fewer attacks for probenecid (34% fewer to 30% more) Relative change: 4% better for probenecid (47% better to 75% worse) NNT ‐ n/a3 |
|
| 550 per 1000 | 528 per 1000 (291 to 962) | |||||
| Serum urate normalisation ≤ 5 mg/dL (≤ 0.3 mmol/L) ‐ not measured | See comment | See comment | Not estimable | ‐ | See comment | Not measured |
| Withdrawal due to adverse events ‐ not reported | See comment | See comment | Not estimable | ‐ | See comment | Not reported |
| Total adverse events ‐ not reported | See comment | See comment | Not estimable | ‐ | See comment | Not reported |
| Pain reduction ‐ not measured | See comment | See comment | Not estimable | ‐ | See comment | Not measured |
| Function ‐ not measured | See comment | See comment | Not estimable | ‐ | See comment | Not measured |
| Tophus regression ‐ not reported | See comment | See comment | Not estimable | ‐ | See comment | Not reported |
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; RR: risk ratio. | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
1 Open‐label study with possible performance and detection bias and unclear risk related to possible attrition bias. 2 Small study (37 participants). Few events resulting in wide CI.
3 Number needed to treat for an additional beneficial outcome (NNTB) or harmful outcome (NNTH) not applicable (n/a) when result is not statistically significant. NNT for dichotomous outcomes calculated using Cates NNT calculator (www.nntonline.net/visualrx/). NNT for continuous outcomes calculated using Wells Calculator (Cochrane Musculoskeletal Group editorial office).