Long-term outcome studies in Takayasu arteritis (TA) are few and limited by small sample size. In this study, we analysed the outcome of treatment in a large series of TA patients with a minimum follow-up period of ≥12 months by objective instruments.
Patients with TA satisfying the 1990 ACR, Ishikawa's, Sharma's or EULAR/PRESS criteria were recruited from our clinics between 1998 and 2016. Only patients with a minimum follow up of 12 months were studied. Data related to clinical presentation, disease extent (DEI.Tak score), activity [Indian Takayasu arteritis clinical activity score, that is, ITAS-A (CRP)] and damage score [Takayasu arteritis damage score (TADS)], angiography and treatment were collected for all patients. Response to treatment was categorised as complete response (CR), partial response (PR) or refractory disease. Patients with sustained CR on prednisolone dose of ≤5mg/day were classified as having sustained inactive disease. Appropriate statistical tests were used for parametric and non-parametric data. Relapse free survival was projected by Kaplan-Meir curve. Cox proportional hazards regression plot was used to compare the efficacy of medications. Predictors of sustained response were identified by logistic regression and a prediction model was constructed.
Among 503 TA patients examined during study period, 251 had follow-up of ≥12 months and were included in this study. Median follow-up duration was 42 months (IQR: 24-81, maximum 240 months). Patients (81.7% females, mean age of 29.2 ± 11.8 years, symptom duration of 24 [6-70] months) were treated by a uniform protocol that included high dose steroids (n = 239) plus concurrent steroid-sparing immunosuppressant (n = 235) with mycophenolate in majority. Biological agents (n = 44 patients) and revascularisation procedures were used in symptomatic patients after control of disease activity. At 1st follow-up, CR (ITAS2010 = 0, CRP < 6mg/L and non-progressive disease on angiography) was observed in 173 (68.9%), partial response (PR) in 42 (16.7%) and no response was seen in only 36 (14%) patients. CR was sustained till the last follow up in 116 (65.9%) of 173 patients with initial CR, while 87 (49.4%) of them achieved sustained inactive disease. Disease activity relapsed at a median duration of 37 (29.9-44.1) months in 56 patients. Cumulative relapse free survival was 93%, 73%, 66% and 52% at 1, 3, 5 and 10 years, respectively. Baseline CRP < 6.2, DEI.Tak < 9 and angiographic type 4 disease predicted sustained inactive disease and a model comprising these parameters showed sensitivity and specificity of 70% and 61.1%. Two fatalities were observed. New vascular lesions during follow up were observed in 50 (19.9%) patients. Overall, 92.8% had at least one period of CR or PR while 7.2% were refractory to treatment till the last follow up. Damage progression (∆TADS > 1) was arrested in 68% of patients and was lower in patients with sustained inactive disease [0 (0-1)] as compared to the rest [1 (0-2.75)], p = 0.000. Both early response as well as cumulative hazard for relapse were similar between patients initiated on 0.5 and 1mg/kg/day steroids.
Our strategy of upfront combination immunosuppressant therapy stabilised disease activity in 92.8% of patients, while 7.2% had true refractory disease. Relapse free survival was 66% at 5 years and 52% at 10 years. Damage progression was arrested in 68% and only 2 fatalities were observed. Initial steroid dose of 0.5mg/kg/day had similar efficacy as 1mg/kg/day dose.