OptumInsight, Health Economics and Outcomes Research, Eden Prairie, MN 55344, USA.
J Med Econ. 2012;15(1):175-84. doi: 10.3111/13696998.2011.632044. Epub 2011 Nov 8.
Bone metastases are common in patients with advanced breast cancer, and place patients at risk for skeletal-related events (SREs) including pathologic fracture, spinal cord compression, hypercalcemia of malignancy, and the need for radiotherapy and/or surgery to bone. These SREs are associated with reduced survival and quality-of-life. The nitrogen-containing bisphosphonates Zometa (zoledronic acid, ZOL) and Aredia (pamidronate disodium, PAM) reduce SRE risk in patients with bone metastases from breast cancer. This database analysis compared SRE and mortality rates in a real-life setting in women with breast cancer receiving ZOL and PAM, and assessed long-term ZOL benefit.
A retrospective, claims-based analysis was conducted using commercial and Medicare Advantage data from >45 US managed-care plans. Eligible adult patients had diagnoses for breast cancer and bone metastasis between 01/01/01 and 12/31/06, continuous enrollment in the health plan, and no evidence of bone metastasis or intravenous bisphosphonate (IV-BP) use for 6 months before their first ZOL or PAM infusion. Patients were followed until disenrollment (including mortality) or end of the analysis period (12/31/07). Persistency was defined as absence of a >45-day gap between IV-BP treatments.
Of 8757 patients (mean age, 58.1 [SD 12.4] years), approximately 30% were treated with ZOL, 15% with PAM, and 55% with no IV-BP. Patients treated with ZOL had a moderately lower incidence of SREs (mean, 36.2 vs 40.0 SREs/100 person-years; p = 0.0707) and significantly lower mortality (mean, 6.5 vs 11.2 deaths/100 person-years; p < 0.001) compared with PAM-treated patients. Longer persistency with ZOL was associated with lower risk of fracture and all SREs (trend-test p = 0.0076 and p = 0.0200, respectively).
Interpretation of this claims-based analysis must be tempered by the inherent limitations of observational data, such as imbalances in patient populations and the potential for bias in treatment selection.
This analysis suggests that fewer than half of breast cancer patients with bone metastases receive IV-BPs. Longer persistence with ZOL was associated with lower SRE risk, and ZOL-treated patients had longer survival and a non-significant trend toward fewer SREs compared with PAM.
在晚期乳腺癌患者中，骨转移很常见，使患者面临骨骼相关事件（SREs）的风险，包括病理性骨折、脊髓压迫、恶性高钙血症以及需要放疗和/或手术治疗骨骼。这些 SREs与降低生存率和生活质量有关。含氮双膦酸盐唑来膦酸（zoledronic acid，ZOL）和帕米膦酸二钠（pamidronate disodium，PAM）可降低乳腺癌骨转移患者的 SRE 风险。这项数据库分析比较了在真实环境中接受唑来膦酸和帕米膦酸治疗的乳腺癌女性的 SRE 和死亡率，并评估了长期唑来膦酸的益处。
使用来自 45 个以上美国管理式医疗计划的商业和医疗保险优势数据库进行回顾性、基于索赔的分析。合格的成年患者在 01/01/01 至 12/31/06 期间有乳腺癌和骨转移的诊断，在健康计划中有连续参保记录，并且在首次接受唑来膦酸或帕米膦酸输注前 6 个月内没有骨转移或静脉内双膦酸盐（IV-BP）的使用证据。患者随访至退出（包括死亡）或分析期结束（12/31/07）。持续性定义为 IV-BP 治疗之间没有超过 45 天的间隔。
在 8757 名患者中（平均年龄 58.1 [12.4] 岁），约 30%接受唑来膦酸治疗，15%接受帕米膦酸治疗，55%未接受 IV-BP 治疗。与接受帕米膦酸治疗的患者相比，接受唑来膦酸治疗的患者 SREs 的发生率（平均，36.2 与 40.0 SREs/100 人年；p=0.0707）和死亡率（平均，6.5 与 11.2 人年死亡/100 人年；p<0.001）均较低。与接受帕米膦酸治疗的患者相比，接受唑来膦酸治疗的患者具有更长的持续性，且 SRE 风险较低（趋势检验 p=0.0076 和 p=0.0200）。
由于患者人群的不平衡和治疗选择的潜在偏差等观察性数据固有的限制，必须对基于索赔的分析进行解释。
这项分析表明，不到一半的乳腺癌骨转移患者接受 IV-BP 治疗。与接受帕米膦酸治疗的患者相比，接受唑来膦酸治疗的患者具有更长的持续性，且 SRE 风险较低，接受唑来膦酸治疗的患者的生存率更高，且 SRE 发生率呈下降趋势，但无统计学意义。
