Evaluation of the efficacy and relapse rates of treatment protocols for moderate acne using isotretinoin based on the global acne grading system: Randomized, controlled, comparative study

Abstract

Protocols for treating acne with isotretinoin have varied widely because some factors associated with relapse and treatment duration have not yet been fully determined. This paper evaluates the effectiveness of conventional, low, and intermittent isotretinoin dosage protocols in the treatment of moderate acne and investigates the relationships between GAGS score, treatment duration and relapse rate. The 107 patients with moderate acne were randomly divided into three groups who received isotretinoin for 24 weeks (Group A: 0.5-1 mg/kg/day; Group B: 0.25-0.4 mg/kg/day; Group C: 0.5-0.7 mg/kg/day for 1 week out of every 4 weeks). The results show that both conventional and continuous low doses achieved full clinical effectiveness with minimum relapse rates. However, fewer side effects and better patient satisfaction were reported with the low dose. Significant differences in GAGS scores after 24 weeks were found between groups B and C (p = 0.037) and between groups A and C (p < 0.001), while no significant differences were found between groups A and B (p = 0.153). It was observed that relapse rate increased with initial GAGS score. The average relapse rate was 58.0% for those with initial GAGS scores of 25-30 compared with 5.5% for those with scores of 19-24. It was also noticed that, among the patients who relapsed, the highest percentage (56.3%) were in the age group <20 years. However, GAGS (beta = 0.646, t = 8.323, p < 0.001) was found to be a better predictor of relapse than age (beta = 0.083, t = 1.073, p = 0.286). These results suggest that initial GAGS score is an important factor in determining the treatment protocol for moderate acne. Furthermore, this study recommends that a low-dose treatment is most suitable when GAGS <25, as it can achieve complete clearance of acne with minimal relapses and side effects.