RESUMEN
INTRODUCTION: We performed a randomized, double-blind, controlled clinical trial comparing intravenous pamidronate and placebo for pain relief in recent osteoporotic vertebral compression fractures (VCF). METHODS: Patients suffered from recent (<21 days), painful, osteoporosis-related VCF. They were randomized to receive daily intravenous infusions of either placebo or 30 mg pamidronate for three consecutive days (total pamidronate: 90 mg). The main criterion for efficacy was improvement in standing pain on a 100-mm visual analogical scale (VAS) at day 7. Secondary criteria were standing pain at days 3 and 30; supine pain at days 3, 7, and 30; patients' overall assessment of improvement; mobility index; and number of "20% responders" and "50% responders" (respectively, 20% and 50% improvement in standing pain at days 7 and 30). Statistical analysis with non-parametric tests was carried out on an intention to treat basis. RESULTS: Thirty-two patients were enrolled in the study; 16 were given placebo and 16 pamidronate. Thirty-one patients were evaluated at day 7 and 26 patients at day 30. VAS pain decreased significantly in both groups at day 7 (placebo -23 mm, pamidronate -42 mm, p<0.01). The difference in pain scores between groups was -23.25 mm (confidence interval (CI) [-42.3; -4.2], p=0.018) at day 7 and -26 mm at day 30 (p=0.03), in favor of pamidronate. At day 7, there were 4 versus 12 "50% responders," respectively, in the placebo and in the pamidronate groups (likelihood ratio: 8.372; p=0.004) and 9 versus 14 "20% responders" (likelihood ratio: 4.038; p=0.044). At day 30, there were 5 versus 10 "50% responders," respectively, in the placebo and in the pamidronate groups, and 7 versus 11 "20% responders." Patients' overall assessment of improvement at day 7 was 37+/-26 mm in the placebo group and 59+/-30 mm in the pamidronate group (p=0.019), and 42+/-26 mm and 72+/-21 mm at day 30 (p=0.07). The two groups did not differ significantly at days 7 and 30 for supine pain, Schober index, or finger-ground distance. No significant adverse reaction related to treatment occurred. CONCLUSION: Pamidronate provides rapid and sustained pain relief in patients with acute painful osteoporotic VCF and is well tolerated. Further investigations are needed to better define the place of pamidronate in the management of painful recent osteoporotic collapse.