Prescription-grade crystalline glucosamine sulfate as an add-on therapy to conventional treatments in erosive osteoarthritis of the hand: results from a 6-month observational retrospective study

OBJECTIVE: To evaluate the efficacy of prescription-grade Crystalline Glucosamine Sulfate (pCGS) as an add-on treatment to conventional therapy, compared to usual therapy alone, in patients with erosive osteoarthritis of the hand (EHOA). METHODS: This 6-month retrospective case–control study included patients with concomitant knee osteoarthritis and symptomatic EHOA. Participants were stratified into two groups based on whether or not pCGS (1500 mg/day) was added to the conventional therapy (education and training in ergonomic principles, exercise and use on-demand of symptomatic drugs) for hand osteoarthritis. Patients were evaluated at baseline, after 3 and 6 months. Primary outcomes were the change from baseline to month 6 in Visual Analogue Scale (VAS) hand pain and in Functional Index for Hand Osteoarthritis (FIHOA) score. A set of secondary parameters was also evaluated. RESULTS: 123 patients were included as follows: 67 treated with pCGS in addition to conventional therapy (pCGS Group) and 56 with conventional therapy alone (Control Group). After 6 months a significant difference in VAS and in FIHOA score (p < 0.01 and p < 0.001, respectively) was observed in favor of pCGS Group. Similar results were found for morning stiffness duration (p < 0.05), health assessment questionnaire (p < 0.01) and physical and mental component score of 36-item short form (p < 0.05 and p < 0.001, respectively). A significant reduction of symptomatic drug consumption at 3 and 6 months was reported in the pCGS Group (p < 0.001). No serious adverse event was recorded in both groups. CONCLUSIONS: Despite all the limitations inherent to an observational study, our results suggest the potential effectiveness of pCGS, when used in combination with conventional therapy in EHOA. Further randomized placebo-controlled trials are needed to confirm these positive findings. TRIAL REGISTRATION: ClinicalTrials.gov, http://www.clinicaltrials.gov, date of registration: February 2, 2022, NCT05237596. The present trial was retrospectively registered. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40520-022-02151-7.