Semi-quantitative thigh magnetic resonance imaging scores in assessing disease activity and determining long-term clinical outcome in idiopathic inflammatory myopathies: a causal mediation analysis.

OBJECTIVES: To evaluate the relationship of thigh MRI (t-MRI) with manual muscle testing-8 (MMT-8), muscle enzymes and autoantibodies. To determine the causal and mediating factors resulting in poor recovery of MMT-8 in inflammatory myositis (IIM). METHODS: This was a single-centre retrospective study in IIM patients. t-MRI was semi-quantitatively scored for muscle oedema, fascial oedema, muscle atrophy and fatty infiltration. Spearman correlation of t-MRI scores was done with muscle enzymes at baseline, and MMT-8 at baseline and on follow-up. Causal mediation analysis was performed with age, sex, symptom duration, autoantibodies, diabetes and BMI as independent variables, follow-up MMT-8 as dependent and t-MRI scores as mediating variables. RESULTS: Baseline evaluation was done on 59 and follow-up on 38 patients. Median follow-up of the cohort was 31 (10-57) months. Baseline MMT-8 negatively correlated with muscle oedema (r = -0755), fascial oedema (r = -0.443) and muscle atrophy (r = -0.343). Creatinine kinase (r = 0.422) and aspartate transaminase (r = 0.480) positively correlated with muscle oedema. Follow-up MMT-8 correlated negatively with baseline atrophy (r = -0.497) and fatty infiltration (r = -0.531). On follow-up, MMT-8 males had positive total effect (estimate (95%CI)) via atrophy [2.93 (0.44, 4.89)] and fatty infiltration [2.08 (0.54, 3.71)]. Antisynthetase antibody had a positive total effect via fatty infiltration [4.50 (0.37, 7.59)]. Age had a negative total effect via atrophy [-0.09 (0.19, -0.01)] and fatty infiltration [-0.07 (-0.15, -0.01)]. Disease duration had a negative total effect via fatty infiltration [-0.18 (-0.27, -0.02)]. CONCLUSION: Baseline fatty infiltration and muscle atrophy resulting from older age, female sex, longer disease duration and absent anti-synthetase antibodies, partly mediate muscle recovery in IIM.

Performance of timed function tests as outcome measures in idiopathic inflammatory myopathy-results from a single-centre cohort.

OBJECTIVE: To evaluate performance of timed function tests (TFTs) in assessing muscle strength and endurance as determined by Manual Muscle Testing 8 (MMT-8) and Functional Index 2 (FI-2), respectively, in idiopathic inflammatory myopathies (IIM). METHODS: This cohort study included 42 IIM patients satisfying 2017 EULAR/ACR criteria. Patients were classified as active (n = 18) or inactive disease (n = 24) based on clinical status at baseline. MMT-8, FI-2, 30 s rise from chair test, 30 s 1 kg arm rise test and 2-min walking distance (2MWD) were administered at baseline, 3 months and 6 months. Pearson rank correlation analysis and receiver operating curves were performed to assess the performance of timed function tests. RESULTS: All patients were followed up at 3 months and 39 completed 6 months' follow-up. All the three TFTs had excellent convergent (r > 0.7, P < 0.05) and divergent validity (P < 0.05). Only 2MWD had moderate to strong correlation with ΔMMT-8 at 3 and 6 months among those with active disease (P = 0.001). All the TFTs correlated with ΔFI-2 in active disease but only Δ2MWD correlated with ΔFI-2 in inactive disease at 6 months (r = 0.506, P = 0.036). At a cut-off of 5% improvement in MMT-8, 2MWD had an area under the curve (AUC) of 0.868 with 95% sensitivity with 2% improvement at 3 months. To detect a 10% ΔMMT-8, Δ2MWD at a cut of 8% and 7% had an AUC of 0.909 and 0.893 with a sensitivity of 92% at 3 and 6 months, respectively (P < 0.05). CONCLUSION: 2MWD is a reliable indicator of muscle strength, endurance and treatment response. The 2MWD can be self-administered by patients, making it a potential patient-reported outcome measure.

Tele-rheumatology for overcoming socioeconomic barriers to healthcare in resource constrained settings: lessons from COVID-19 pandemic.

OBJECTIVES: To assess acceptability of teleconsultation among the socioeconomically marginalized sections of patients with rheumatic and musculoskeletal diseases (RMDs), to identify the socioeconomic barriers in continuing rheumatology care during the COVID-19 crisis and to identify patients who could benefit by shifting to tele-rheumatology consultations. METHODS: This was a cross sectional analytical study done at a tertiary care teaching hospital in India including patients with RMDs who were not on biological diseases modifying agents. Assessment of disease status, socioeconomic status and economic impact of COVID-19 was done via tele-consultation. RESULTS: Out of the 680 patients satisfying inclusion criteria, 373 completed the study. The format was found easy by 334 (89.6%) of them and 284 (76.1%) considered tele-rheumatology better than in-person consultation. During the pre-COVID months, the median monthly per capita income of the families of our patients and cost of illness was Indian rupees (INR) 2000 (US$ 26) and INR 1685 (US$ 21.91), respectively. Families whose financial needs were met (OR = 0.38, 95% CI: 0.239, 0.598) or those with schooling upto at least secondary school (OR = 0.442, 95% CI: 0.260, 0.752) (P =0.002) were less likely to stop prescription drugs. In a hypothetical model, 289 (77.4%) could be successfully switched to tele-rheumatology follow-up. CONCLUSION: The acceptability of tele-rheumatology among socioeconomically marginalized patients with RMDs is good. During times of crisis, patients from poorer strata of society and lower educational background are likely to abruptly stop medications. Switching to a telemedicine-based hybrid model is likely to improve drug adherence with substantial savings on loss of pay and out of pocket expenditure.

Effect of skin phototype on quantitative nailfold capillaroscopy.

Objectives: To determine the impact of Fitzpatrick scale-based skin phototype on visualization of capillary density using nailfold capillaroscopy in healthy Indian adults. Methods: In this cross-sectional study, healthy adults were examined for nailfold capillaroscopy findings utilizing a portable capillary microscope at 800× magnification. Photographs of two contiguous areas measuring 1 mm2 each of the distal row of capillaries were captured. Images were captured from the central area of all fingers except thumb in both hands. Capillary density and morphology of nailfold capillaroscopies were assessed by two blinded assessors. The nailfold capillaroscopy parameters were compared between the Standard Fitzpatrick scale-based skin phototypes. Results: A total of 118 healthy adults were enrolled in the study. Type III, IV, V, and VI skin phototypes were seen in 27 (22.90%), 32 (27.19%), 29 (24.58%), and 30 (25.42%) participants, respectively. All participants (100%) had normal nailfold capillaroscopy morphology and architecture. Zero capillaries were visible in 11 fingers among 5 patients (4.24%) and all of them had Type VI phototype. The median capillary density per mm was 5.19 (interquartile range = 4.37-6.75) with 90 (76.27%) participants having less than seven capillaries. The median average capillary density was significantly different (p-value < 0.0001) across Type III (8.13, interquartile range = 6.44-8.88), Type IV (5.67, interquartile range = 4.41-6.98), Type V (4.94, interquartile range = 4.19-5.38), and Type VI (4.53, interquartile range = 3.72-4.91) phototypes (p < 0.05). Conclusion: The number of capillaries visualized during nailfold capillaroscopy decreases as the skin pigmentation increases. There is a need to redefine the nailfold capillaroscopy density and avascularity by taking skin phototype as one of the determinants before labeling a nailfold capillaroscopy finding with less visualized capillaries as abnormal.