Study selection
This network meta-analysis was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (26).
A total of 38 articles, including 41 trials (7–15, 27–55), were included. The selection criteria is shown in Supplementary appendix Fig. 1. Five treatment arms (Anti-NGF, potent opioid, weak opioid, selective COX-2 inhibitor, and NSAIDs ) and eight treatment arms (celecoxib, etoricoxib, rofecoxib, Iburofen, naproxen, diclofenac, paracetamol/acetaminophen and placebo) were included into the network of the main and subgroup analyses, respectively (Fig. 1).
Study Characteristics
A total of 20489 patients were included in to the study. Among the 41 eligible articles, only one study with 385 patients was on hand-joint OA. Across the trials, the mean age of the patients was 61.25 years (ranged from 57.41 to 70.00 years), the proportion of male patients was 32.26% (ranged from 19.57–54.03%), and the median follow-up was 84 days (IQR 42–84 days). The number of assessed patients for each treatment were 5408 (NSAIDs), 4131(selective COX-2 inhibitor), 3108 (anti-NGF), 1405 (weak opioids), and 1274 (potent opioids).
The baseline characteristics of the included studies are shown in Supplementary appendix Table 1. The methodological quality and risk of bias were evaluated for all included trials (Supplementary appendix Table 2). Based on this results, the main contributing factors to risks of bias were performance bias, selection bias, and attrition bias.
Table 1
Characteristics of the included comparisons and the results of direct pair-wise meta-analysis(FU, follow-up; No. of pts, number of patients included; No. of trials, number of trials included into direct pair-wise meta-analysis; SMD, standardised mean difference)
Comparison | No. of trials | No. of pts | Target joint | Mean age (range) | Male % | Mean FU periods (days, range) | SMD (95%CI) for pain relief |
Anti-NGF vs placebo | 9 | 2348 | Hip and Knee | 59.98 (57.41–62.32) | 0.3667 | 102.67 (56–224) | 4.182(3.778,4.586) |
Potent opioids vs placebo | 5 | 1528 | Hip and Knee | 61.10 (57.41–65.52) | 0.3662 | 81.2 (14–112) | 0.807 (-1.527,3.140) |
Weak opioids vs placebo | 2 | 805 | Hip and Knee | 59.09 (58.10-60.02) | 0.3723 | 84 | 3.451(1.722,5.180) |
Selective cox-2 inhibition vs placebo | 9 | 2917 | Hip and Knee | 62.81 (60.02–64.77) | 0.2863 | 60.67 (42–84) | 4.775(2.836,6.714) |
NSAIDs vs placebo | 20 | 6833 | Hand, Hip and Knee | 62.55 (58.66-70.00) | 0.299 | 55.65 (21–84) | 2.573(1.789,3.357) |
Table 2
Detailed results of network meta-analysis for pain (Red) and function (Blue) (Data are standardised mean difference, from the top left to the bottom right, higher comparator vs lower comparator, and their related 95% CI)
Anti-NGF | 2.34 (0.38,4.29) | 2.48 (-0.93,5.89) | 2.87 (1.16,4.57) | 3.70 (1.43,5.96) | 4.90 (3.46,6.33) |
1.33 (-0.55,3.21) | Selective cox-2 inhibition | 0.15 (-3.09,3.38) | 0.53 (-0.77,1.84) | 1.36 (-1.07,3.80) | 2.56 (1.17,3.95) |
1.22 (-2.07,4.51) | -0.11 (-3.23,3.00) | Weak opioids | 0.39 (-2.83,3.60) | 1.22 (-2.47,4.91) | 2.42 (-0.68,5.52) |
2.33 (0.69,3.96) | 1.00 (-0.24,2.23) | 1.11 (-1.99,4.20) | NSAIDS | 0.83 (-1.42,3.09) | 2.03 (0.97,3.09) |
3.35 (1.16,5.53) | 2.02 (-0.33,4.36) | 2.13 (-1.44,5.69) | 1.02 (-1.15,3.19) | Potent opioids | 1.20 (-0.81,3.21) |
4.25 (2.87,5.63) | 2.92 (1.58,4.26) | 3.03 (0.04,6.02) | 1.92 (0.92,2.93) | 0.90 (-1.04,2.84) | Placebo |
Primary Efficacy Endpoint
Direct pair-wise meta-analysis
The efficacies of all the drugs were superior to placebo, for pain relief except for potent opioid with no significant difference (0.807, 95%Cis [-1.527 to 3.140]). Notably, Anti-NGF had the highest significant, for pain relief (SMD 4.817, 95% Cis [3.077 to 6.557]). The details of the pairwise meta-analysis for all drugs compared with placebo are shown in Table 1.
Network Meta-analysis
A total of 38 trials were analyzed. No significant inconsistency was reported in loop-inconsistency estimates, node-split tests, and global inconsistency tests. The consistency model was statistically significant than the inconsistency model.
Anti-NGF was the most efficacious drug (SMD compared with placebo 4.25, 95% CIs [2.87 to 5.63]) for OA pain relief. The potent opioid drug had the lowest efficacy (SMD 0.90, 95% CIs [-1.04 to 2.84]) (Figure 2 and Table 2). Based on the SUCRA value, Anti-NGF was the most efficacious drug in pain relief (SUCRA=93.7%), followed by selective COX-2 inhibitor (SUCRA=69.0%), and lastly opioids (SUCRA=67.3%). The details of the SURCA rank are shown in Supplementary appendix Table 3.
The subgroup analysis results showed a consistent trend, even after eliminating did all non-funded trials (10 trials). Anti-NGF was still the most efficacious drug for pain relief (SURCA 92.4%, SMD=4.30, 95%CIs [2.85 to 5.74]). The detailed results are shown in the Supplementary appendix Table 4.
Secondary Efficacy Endpoint
Direct pair-wise meta-analysis
Except for the potent opioids (SMD 1.058, 95%Cis [-1.012 to 3.127]), there was a significant difference in efficacy both in the Anti-NGF and selective COX-2 inhibitor drugs compared to placebo. Anti-NGF had the highest efficacy for physical function improvement (SMD 5.108, 95% Cis [3.165 to 7.051]). The details of the pairwise meta-analysis for all drugs compared with placebo are presented in Table 1.
Network meta-analysis
A total of 38 trials were analyzed. No significant inconsistency was reported. The consistency model was statistically significant compared to the inconsistency model. Similarly, Anti-NGF drug had the highest efficacy for physical function improvement (SMD 4.90, 95% CIs [3.46 to 6.33]) (Figure 2). The lowest efficacy was reported in potent opioid drug (SMD 1.20, 95% CIs [-0.81 to 3.21]) (Figure 2 and Table 2). For physical function improvement, the most efficacious drug based on SURCA, was Anti-NGF (SUCRA=98.3%), followed by selective COX-2 inhibitor (SUCRA=63.5%) and opioids (SUCRA=56.7%) (Supplementary appendix Table 3). There was no significant difference in the subgroup analysis of the trials with commercial funding. For physical function, Anti-NGF had the highest efficacy (SUCRA 97.6%, SMD 4.96, 95% CIs [3.42 to 6.50]) (Supplementary appendix Table 4).
Primary Safety Endpoint
Direct pair-wise meta-analysis
Except for selective COX-2 inhibitor (OR 0.742, 95% CIs [0.436 to 1.261]), There were significant differences in both Anti-NGF and Opioids in the withdrawal rate due to AEs (Supplementary appendix Table 5).
Network meta-analysis
In the withdrawal due to AEs network, a total of 36 trials were assessed. Loop-inconsistency estimates, node-split tests, and global inconsistency tests were performed, and no inconsistency was reported.
Significantly higher withdrawal rates due to AEs were reported in potent opioids (OR 8.63, 95%CIs [5.42, 13.77]), weak opioids (OR 3.27, 95%CIs [1.89, 5.66]), and NSAIDs (OR 1.36, 95%CIs [1.04, 1.77]) compared to placebo. Selective COX-2 inhibitor (SURCA = 93.4%) was reported as the most safe drug, followed by anti-NGF (SURCA=53.5%), and NSAIDs (SURCA=50.5%) (Supplementary appendix Table 3). The subgroup analysis showed that there was no significant change in results, after adjusting the network based on whether trials were funded (Supplementary appendix Table 4). There was no statistical difference reported after excluding the trials with short follow-up. The cluster-rank plots of primary efficacy and primary safety indicated the safest drug was selective Cox-2 inhibition ( Supplementary appendix Figure 2).
Network meta-analysis
In the headache network, the most efficacious drug was NSAIDs (OR 0.82, SURCA 90.3%, 95% CIs [0.63 to 1.06]). However, no significant differences were reported between the remaining treatments and placebo.
NSAIDs (OR 1.48, 95% CIs [1.04 to 2.13]), weak opioids (OR 3.90, 95% CIs [1.82 to 8.36]) and potent opioids (OR 6.33, 95% CIs [3.37 to 11.90]) had significantly higher risks for nausea AEs. The incidence rates of peripheral sensation abnormality AEs was significantly higher in anti-NGF (OR 3.64, 95% CIs [1.87 to 7.10]), weak opioids (OR 5.25, 95% CIs [1.95 to 14.15]) and potent opioids (OR 5.39, 95% CIs [2.41 to 12.06]) (Table 3). No subgroup analysis was conducted for secondary safety endpoints because of the insufficient number of trials included.
Table 3. Adverse effects of different treatment compared with placebo according to direct pair-wise meta analysis and network meta-analysis (AE, adverse effect; PSA, peripheral sensation abnormality; SUCRA, surface under the cumulative ranking.)
Treatment | OR(95%CI) | SURCA(%) |
Direct | Network meta-analysis |
Withdrawl due to AEs | | | |
| Placebo | Reference | Reference | 82.3 |
| Anti-NGF | 1.677(1.045,2.692) | 1.36 (0.82,2.27) | 53.5 |
| Potent Opioids | 5.265(3.705,7.482) | 8.63 (5.42,13.77) | 0.1 |
| Weak Opioids | 2.798(1.348,5.807) | 3.27(1.89,5.66) | 20.1 |
| Selective cox-2 inhibition | 0.742(0.436,1.261) | 0.89 (0.64,1.24) | 93.5 |
| NSAIDs | 1.272(1.028,1.573) | 1.36(1.04,1.77) | 50.5 |
Headache AEs | | | |
| Placebo | Reference | Reference | 53.3 |
| Anti-NGF | 0.970(0.634,1.483) | 1.03 (0.68,1.57) | 49.3 |
| Potent Opioids | 1.283(0.897,1.837) | 1.19 (0.78,1.82) | 29.2 |
Continued |
| Weak Opioids | 1.305(0.709,2.399) | 1.41 (0.88,2.25) | 12.4 |
| Selective cox-2 inhibition | 0.748(0.528,1.060) | 0.93 (0.68,1.27) | 65.4 |
| NSAIDs | 0.928(0.733,1.175) | 0.82 (0.63,1.06) | 90.3 |
Nause AEs | | | |
| Placebo | Reference | Reference | 74.2 |
| Anti-NGF | 0.962(0.504,1.837) | 0.79 (0.41,1.53) | 88.7 |
| Potent Opioids | 4.519(3.212,6.358) | 6.33 (3.37,11.90) | 3.3 |
| Weak Opioids | 3.131(2.054,4.775) | 3.90 (1.82,8.36) | 17.0 |
| Selective cox-2 inhibition | 0.825(0.398,1.708) | 0.99 (0.64,1.52) | 75.8 |
| NSAIDs | 1.432(0.947,2.165) | 1.48 (1.04,2.13) | 41.1 |
Psa AEs | | | |
| Placebo | Reference | Reference | 82.7 |
| Anti-NGF | 4.184(2.010,8.707) | 3.64 (1.87,7.10) | 30.7 |
| Potent Opioids | 5.331(2.731,10.407) | 5.39 (2.41,12.06) | 14.2 |
| Weak Opioids | 8.371(2.935,23.870) | 5.25 (1.95,14.15) | 15.4 |
| Selective cox-2 inhibition | 0.777(0.021,28.890) | 0.96 (0.39,2.39) | 82.6 |
| NSAIDs | 0.966(0.633,1.473) | 1.13 (0.67,1.90) | 74.4 |
Subgroup analysis of efficacy between NSAIDs and selective COX-2 inhibitor
A total of 24 trials, assessing the efficacy of NSAIDs or selective COX-2 inhibitor, were included. Etoricoxib was the most efficacious drug for both pain relief (SMD 3.20, 95% Cis [1.17 to 5.24]) and function improvement (SMD 3.41, 95% Cis [1.88 to 4.93]). All drugs had significantly higher efficacies compared to placebo for both pain relief and function improvement (Figure 2 and Supplementary appendix Table 6). However, no significant difference was reported between different drugs. Based on the cluster-rank plot, etoricoxib was the efficacious drug (Supplementary appendix Figure 2).
Secondary Safety Endpoint
After selection of the studies, the incidence rates of the three most common AEs, including nausea, headache, and peripheral sensation abnormality (paresthesia and pruritus) were selected for secondary safety endpoints. A total of 33 trials were assessed.
Direct Pair-wise Meta-analysis
There were no significant difference in headache AEs among the three drugs from the pair-wise meta-analyses. However, potent opioids and weak opioids had significantly higher risks for nausea or peripheral sensation abnormality AEs. Besides, Anti-NGF had significantly higher risk for peripheral sensation abnormality AEs (Table 3).