TOPLINE

Oral vitamin B3 (nicotinamide) at 500 mg twice daily for 14 days improved nailfold videocapillaroscopy (NVC) patterns in around 45% of participants with primary or scleroderma-related Raynaud phenomenon (RP), with increased normal capillaries and reduced abnormal features. Participants with primary RP experienced improvements in RP-related quality of life.

METHODOLOGY

• A 6-week prospective, longitudinal, within-participant crossover intervention study enrolled 38 adult participants (20 with primary RP and 18 with scleroderma-related RP) from rheumatology clinics within the Australian Capital Territory.
• Participants underwent a three-phase study design comprising a 2-week baseline period, a 2-week period of oral vitamin B3 supplementation at 500 mg twice daily, and a 2-week vitamin B3 washout period. They were observed during the winter months (May to September 2025) when mean daily temperatures were ≤10 °C.
• Primary endpoints were adherence to vitamin B3, changes in NVC patterns and parameters (assessed using AI-based software), RP frequency and severity (assessed via the Raynaud Condition Score [RCS] diary), and RP-related quality of life (assessed via the Short-Form Assessment of Systemic Sclerosis-Associated Raynaud's Phenomenon questionnaire).
• NVC assessments involved automated pattern classification and quantitative measures of capillary density, limb diameters, morphology, and abnormal features.
• Participants completed daily paper diaries noting RCS parameters such as the number of RP episodes per day, the average duration of episodes in minutes, and the severity of episodes; the maximum and minimum daily temperatures; and any changes in medication throughout the 6-week period.

TAKEAWAY

• Adherence to vitamin B3 supplementation was excellent, with only 1.3% of doses missed. Only 13.2% of participants reported potential adverse events, including mild headache in 4 participants with primary RP and melena in one male participant with scleroderma who discontinued treatment.
• Overall, 44.7% of participants demonstrated NVC pattern improvement (P < .001), and 55.2% showed no change. NVC pattern improvements were statistically significant after vitamin B3 supplementation in both the primary RP (P < .008) and scleroderma-related RP (P < .014) groups.
• Overall, the mean percentage of normal capillaries increased significantly after vitamin B3 supplementation, with significant reductions in the mean percentages of abnormal shapes and giant capillaries (P < .05 for all).
• In the primary RP group, the percentage of participants achieving the Patient-Acceptable Symptom State for quality of life increased from 45% at baseline to 75% after vitamin B3 supplementation and remained at 75% after washout, with the mean score after washout being below the Patient-Acceptable Symptom State threshold (P = .03); the scleroderma-related RP group showed no significant improvements in RP-related quality of life or RCS severity.

IN PRACTICE

"[O]ral nicotinamide 500 mg twice daily for 14 days was largely safe and well tolerated in both primary and scleroderma-related RP groups," the authors of the study wrote.

SOURCE

The study was led by Mogeshni Govender, MD, Canberra Hospital in Garran, Australian Capital Territory, Australia. It was published online on August 7 in ACR Open Rheumatology.

LIMITATIONS

The study lacked a placebo-controlled group. The short treatment duration and follow-up may not reflect long-term structural microvascular changes, especially in scleroderma, where vascular remodeling occurs over a longer period. NVC imaging might be limited in individuals with increased skin pigmentation due to difficulty in capillary visualization.

DISCLOSURES

No specific funding or conflicts of interest were reported.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.