Studies reporting on muscle strength, endurance and functional disability and pain
| Study | Disease duration (years)* | Disease activity | Pain severity* | Findings |
| SF-36 BP (additive 0–100, norm-based mean 50, SD 10); lower score, more pain | ||||
| Ponyi et al28 | Median (range) 8.9 (3.0–22.8) | Active disease 13% | Mean±SD DM: 54±18 PM: 58±20 OM: 66±18 | Pain correlated weakly with MMT8 (higher scores, stronger; r=−0.27, p=0.01) and moderately with HAQ-DI (higher scores, more limitation; r=0.52, p<0.001) |
| Regardt et al32 | Mean±SD 6.8±5.5 | N/A | Mean All: 58 DM:55 PM: 58 | Pain not significantly correlated with grip strength or hand mobility |
| Xu et al43 | Median (IQR) 5 (2.5–7.4) | VAS score (0–100) Median (IQR) PhGA: 17 (5–31) PtGA: 29 (11–49) | Mean±SD 63±26 | Pain weakly correlated with MMT-8 (higher score, stronger; r=0.30, p=0.03) |
| van de Vlekkert et al35 | Median Baseline: 0.3 Scheduled visit at 18 months from baseline | At inclusion: early AIM with active disease 18 months: remission 33%, polyphasic 33%, chronic course 35% | Mean Baseline: 42 18 months: 70 Last follow-up*: 65 | Pain worse with higher disability measured with the modified Rankin score |
| Poulsen et al36 | Median (IQR) 6.7 (4.1–13) | VAS score (0–10) Median (IQR) PhGA 4.4 (2.2–6.7) | Mean±SD 60+26 | Pain not associated with MMT-8 (higher score, stronger; β=0.09, p=0.88) in multiple linear regression |
| Alexanderson et al16 | Fixed visit 1 year after diagnosis | VAS score (0–100) Median (IQR) PhGA: 10 (4–24) PtGA: 27 (7–49) | Median (IQR) 74 (51–74) | BP scores weakly correlated with FI2 (higher scores, less limitation; r=0.36, 95% CI 0.05 to 0.61). No significant correlation with MMT-8 (higher score, stronger; r=0.20, 95% CI −0.12 to 0.49) |
| VAS score (0–100); higher score, more pain | ||||
| Heikkila et al24 | Mean±SD 6.4±6.1 | 68% stable medication for >3 months, 27% immunosuppression reduction in previous month | Mean±SD 26±27 | Pain moderately correlated with Functional Index (higher scores, less limitation; r=−0.52, p<0.01) at baseline |
| Baschung Pfister et al17 | Median (IQR) 1.5 (0.3–4.5) | Acute 19% Subacute 15% Chronic 67% | Median (IQR) 14 (0–31) | Pain weakly correlated with Myositis Activity Profile (higher score, more limitation; r=0.38, 95% CI 0.10 to 0.62) |
| Saygin et al42 | Mean±SD 3±4.2 | VAS score (0–10) Mean±SD 3.1±2.3 | Mean±SD 2.7±2.6 | Pain moderately correlated with PROMIS PF-20 (higher score, less limitation; r=−0.60, p<0.0001), SF-36 PF-10 (higher score, less limitation; r=−0.62, p<0.0001) and HAQ-DI (higher score, more limitation; r=0.60, p<0.0001) |
*If not shown, measure of dispersion not provided.
AIM, autoimmune inflammatory myopathy; DM, dermatomyositis; FI2, Functional Index 2; HAQ-DI, Health Assessment Questionnaire–Disability Index; MMT-8, Manual Muscle Testing-8; N/A, not available; OM, overlap myositis; PhGA, Physician Global Assessment; PM, polymyositis; PROMIS PF-20, Patient-Reported Outcomes Measurement Information System physical function-20; PtGA, Patient Global Assessment; SF-36 BP, 36-Item Short Form Bodily Pain; VAS, visual analogue scale.