Kobelt Gisela, Andlin-Sobocki Patrik, Maksymowych Walter P
European Health Economics SAS, Mulhouse, France.
J Rheumatol. 2006 Feb;33(2):289-95.
The use of biological agents in the treatment of ankylosing spondylitis (AS) has emphasized the need for information about the current burden of the disease to estimate the cost-effectiveness of these drugs. We investigated resource utilization and utility of patients with AS in Canada.
A cross-sectional retrospective observational study was performed in a cohort of 545 patients with AS in Alberta, Ontario, British Columbia, and Manitoba. Patients completed a questionnaire asking about their healthcare consumption, out of pocket expenses, work capacity, and need for informal care during the past 3 months. Patients' current functional status and disease activity level was assessed using the Bath AS functional and disease activity indexes (BASFI and BASDAI), and utility was determined using the EQ-5D 5-dimensional health status classification. Descriptive analysis was performed to estimate costs and utility for the sample and by level of disease severity.
Patients' mean age was 49.6 years and the mean disease duration was 22.3 years; 64% were male, and 63% of patients in the sample were working. The mean BASDAI score was 4.3 and BASFI 3.6, although 13% of patients in the sample had a BASFI score > or = 7. The mean annual cost per patient is estimated at 9,008 Canadian dollars (SD 17,724 Canadian dollars), and direct healthcare represented 28.9% of these costs. Patients' out of pocket costs represented 33.1%, and lost work capacity accounted for 38%. Costs increased significantly with diminishing physical function and high disease activity, covering a range of 4,000 Canadian dollars to 30,000 Canadian dollars per patient and year. The estimated cost-increase per unit-increase in the BASFI score at values < 5 was around 1,000 Canadian dollars, and more than 5,000 Canadian dollars at values > 7. The mean utility was 0.65 (SD 0.23). Utility was significantly correlated with age, sex, BASFI, and BASDAI, covering a range from 0.87 for patients with BASFI/BASDAI < or = 2 to 0.20 for patients with BASFI/BASDAI > or = 8. On average, utility decreased by 0.075 for each unit-increase in the BASFI.
All types of costs accelerate steeply with increasing loss of function (BASFI) and disease activity (BASDAI) in patients with AS, while utility decreases significantly. Treatments that control disease activity and maintain patients' function are likely to offset the high cost and low quality of life of severe disease. Our findings provide information on the burden of AS and a baseline for assessing the cost-effectiveness of the new biological agents in this indication.
在强直性脊柱炎（AS）治疗中使用生物制剂凸显了了解该疾病当前负担以评估这些药物成本效益的必要性。我们调查了加拿大AS患者的资源利用情况和效用。
在艾伯塔省、安大略省、不列颠哥伦比亚省和马尼托巴省的545例AS患者队列中进行了一项横断面回顾性观察研究。患者完成了一份问卷，询问他们在过去3个月的医疗保健消费、自付费用、工作能力以及对非正式护理的需求。使用巴斯强直性脊柱炎功能和疾病活动指数（BASFI和BASDAI）评估患者当前的功能状态和疾病活动水平，并使用EQ - 5D五维健康状态分类法确定效用。进行描述性分析以估计样本以及按疾病严重程度分层的成本和效用。
患者的平均年龄为49.6岁，平均病程为22.3年；64%为男性，样本中63%的患者在工作。BASDAI平均评分为4.3，BASFI为3.6，尽管样本中有13%的患者BASFI评分≥7。估计每位患者每年的平均成本为9008加元（标准差17724加元），直接医疗保健费用占这些成本的28.9%。患者的自付费用占33.1%，工作能力丧失占38%。随着身体功能下降和疾病活动度增加，成本显著增加，每位患者每年的费用范围为4000加元至30000加元。BASFI评分＜5时，每增加一个单位，估计成本增加约1000加元；评分＞7时，增加超过5000加元。平均效用为0.65（标准差0.23）。效用与年龄、性别、BASFI和BASDAI显著相关，范围从BASFI/BASDAI≤2的患者的0.87到BASFI/BASDAI≥8的患者的0.20。平均而言，BASFI每增加一个单位，效用下降0.075。
对于AS患者，随着功能丧失（BASFI）和疾病活动度（BASDAI）增加，所有类型的成本都急剧上升，而效用显著下降。控制疾病活动并维持患者功能的治疗可能会抵消严重疾病的高成本和低生活质量。我们的研究结果提供了关于AS负担的信息以及评估该适应症中新生物制剂成本效益的基线。
