Background 

Previous studies on medical costs in patients with hip fractures have focused on medical costs incurred for a short period after the injury. However, patients often had comorbidities before their hip fractures that would have affected medical costs even had they not sustained a fracture. Consequently, these studies may have overestimated the costs associated with hip fractures and did not characterize the duration of increased medical costs adequately. Without knowing this crucial information, it is difficult to craft thoughtful health policy to support these patients’ needs.

Questions/purposes 

(1) To compare the direct medical costs for 5 years before fracture and up to 5 years after injury in a group of patients who underwent hip fracture surgery with a matched group of patients who did not experience a hip fracture, (2) to analyze the duration over which the increased direct medical costs associated with a hip fracture continues, and (3) to analyze whether there is a difference in direct medical costs according to age group using a nationwide claims database in South Korea.

Methods 

The National Health Insurance Service Sample cohort in South Korea consisted of 1 million patients who were selected using a systematic, stratified, random sampling method from 48,222,537 individuals on December 31, 2006. Under a compulsory social insurance system established by the National Health Insurance Act, all patients were followed until 2015. Patients with hip fractures and matched controls were selected from the National Health Insurance Service sample of South Korea. Patients with hip fractures were defined as those who were hospitalized with a diagnosis of femoral neck fracture or intertrochanteric fracture and who underwent surgical treatment. We excluded patients with hip fractures before January 1, 2007 to ensure a minimum 5-year period that was free of hip fractures. Patients with hip fractures were matched with patients of the same age and gender at the date of admission to an acute care hospital for surgery (time zero). If patients with hip fractures died during the follow-up period, we performed matching among patients whose difference from the time of death was within 1 month. This method of risk-set matching was repeated sequentially for the next patient until the last patient with a hip fracture was matched. We then sequentially performed 1:5 random sampling for each risk set. A total of 3583 patients in the hip fracture cohort (patients with hip fractures) and 17,915 patients in the matched cohort (those without hip fractures) were included in this study. The mean age was 76 ± 9 years, and 70% were women in both groups. Based on the Charlson comorbidity index score, medication, and medical history, the patients with hip fractures had more comorbidities. Person-level direct medical costs per quarter were calculated for 5 years before time zero and up to 5 years after time zero. Direct medical costs were defined as the sum of that insurer’s payments (that is, the National Health Insurance Service’s payments), and that patient’s copayments, excluding uncovered payments. We compared direct medical costs between patients with hip fractures and the patients in the matched cohort using a comparative interrupted time series analysis. The difference-in-difference estimate is the ratio of the differences in direct medical costs before and after time zero in the hip fracture cohort to the difference in direct medical costs before and after time zero in the matched cohort; the difference in difference estimates were calculated each year after injury. To identify changes in direct medical cost trends in patients with hip fractures and all subgroups, joinpoint regression was estimated using statistical software.

Results 

The direct medical costs for the patients with hip fractures were higher than those for patients in the matched cohort at every year during the observation period. The difference in direct medical costs between the groups before time zero has increased every year. The direct medical costs in patients with hip fractures was the highest in the first quarter after time zero. Considering the differential changes in direct medical costs before and after time zero, hip fractures incurred additional direct medical costs of USD 2514 (95% CI 2423 to 2606; p < 0.01) per patient and USD 264 (95% CI 166 to 361; p < 0.01) per patient in the first and second years, respectively. The increase in direct medical costs attributable to hip fracture was observed for 1.5 to 2 years (difference-in-difference estimate at 1 year 3.0 [95% CI 2.8 to 3.2]; p < 0.01) (difference-in-difference estimate at 2 years 1.2 [95% CI 1.1 to 1.3]; p < 0.01; joinpoint 1.5 year). In the subgroups of patients younger than 65, patients between 65 and 85, and patients older than 85 years of age, the increase in direct medical costs attributable to hip fracture continued up to 1 year (difference-in-difference estimate ratio at 1 year 2.7 [95% CI 2.1 to 3.4]; p < 0.01; joinpoint 1 year), 1.5 to 2 years (difference-in-difference estimate ratio at 1 year 2.8 [95% CI 2.6 to 3.1]; p < 0.01; difference-in-difference estimate ratio at 2 years 1.2 [95% CI 1.1 to 1.3]; p < 0.01; joinpoint 1.5 years), and 39 months to 5 years (difference-in-difference estimate ratio at 1 year 5.2 [95% CI 4.4 to 6.2]; p < 0.01; difference-in-difference estimate ratio at 5 years 2.1 [95% CI 1.4 to 3.1]; p < 0.01; joinpoint 39 months) from time zero, respectively.

Conclusion 

The direct medical costs in patients with hip fractures were higher than those in the matched cohort every year during the 5 years before and after hip fracture. The increase in direct medical costs because of hip fractures was maintained for 1.5 to 2 years and was greater in older patients. Based on this, we suggest that health policies should focus on patients’ financial and social needs, with particular emphasis on the first 2 years after hip fracture with stratification based on patients’ ages.

Level of Evidence 

Level II, economic analysis.

中文翻译：

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髋部骨折患者和匹配队列的长期直接医疗费用的比较间断时间序列分析：一项大型数据库研究

背景 

先前关于髋部骨折患者医疗费用的研究主要集中在受伤后短期内产生的医疗费用。然而，患者在髋部骨折之前经常患有合并症，即使他们没有骨折，也会影响医疗费用。因此，这些研究可能高估了与髋部骨折相关的费用，并且没有充分描述医疗费用增加的持续时间。如果不了解这一重要信息，就很难制定周到的健康政策来支持这些患者的需求。

问题/目的 

(1) 比较接受髋部骨折手术的一组患者与未经历髋部骨折的匹配组患者骨折前 5 年和受伤后 5 年的直接医疗费用，(2) 分析与髋部骨折相关的直接医疗费用持续增加的持续时间，以及（3）使用韩国全国索赔数据库分析不同年龄组的直接医疗费用是否存在差异。

方法 

韩国国民健康保险服务样本队列由 2006 年 12 月 31 日通过系统、分层、随机抽样方法从 48,222,537 名个体中选出的 100 万名患者组成。根据《国民健康保险法》建立的强制社会保险制度，所有患者均随访至 2015 年。髋部骨折患者和匹配对照患者均选自韩国国民健康保险服务样本。髋部骨折患者被定义为因股骨颈骨折或股骨粗隆间骨折而住院并接受手术治疗的患者。我们排除了 2007 年 1 月 1 日之前发生髋部骨折的患者，以确保至少 5 年内没有发生髋部骨折。将髋部骨折患者与入院急症护理医院手术之日（零时间）时相同年龄和性别的患者进行匹配。如果髋部骨折患者在随访期间死亡，我们对与死亡时间相差在1个月以内的患者进行匹配。对下一位患者依次重复这种风险设置匹配方法，直到匹配最后一位髋部骨折患者。然后，我们对每个风险集依次进行 1:5 随机抽样。本研究共纳入髋部骨折队列（髋部骨折患者）3583 名患者和匹配队列（无髋部骨折患者）17,915 名患者。平均年龄为 76 ± 9 岁，两组中 70% 为女性。根据查尔森合并症指数评分、药物治疗和病史，髋部骨折患者有更多合并症。每季度个人直接医疗费用的计算范围为零时间之前的 5 年和零时间之后的 5 年。直接医疗费用定义为保险公司支付的费用（即国民健康保险公团支付的费用）和患者自付费用的总和，不包括未承保的费用。我们使用比较中断时间序列分析比较了髋部骨折患者与匹配队列中的患者之间的直接医疗费用。双重差分估计是髋部骨折队列中零时间前后的直接医疗费用差异与匹配队列中零时间前后直接医疗费用差异的比率；受伤后每年计算差异估计值的差异。为了确定髋部骨折患者和所有亚组的直接医疗费用趋势的变化，使用统计软件估计了连接点回归。

结果 

观察期间每年髋部骨折患者的直接医疗费用均高于对照组患者。零时间之前各组之间的直接医疗费用差异每年都在增加。髋部骨折患者的直接医疗费用在零时后第一季度最高。考虑到零时间之前和之后直接医疗费用的差异变化，髋部骨折每位患者产生的额外直接医疗费用为 2514 美元（95% CI 2423 至 2606；p < 0.01），每名患者额外直接医疗费用为 264 美元（95% CI 166 至 361；p）。每个患者在第一年和第二年分别< 0.01)。髋部骨折导致的直接医疗费用增加持续 1.5 至 2 年（1 年时的双重差分估计为 3.0 [95% CI 2.8 至 3.2]；p < 0.01）（2 年时的双重差分估计）年 1.2 [95% CI 1.1 至 1.3]；p < 0.01；连接点 1.5 年）。在 65 岁以下患者、65 岁至 85 岁患者以及 85 岁以上患者亚组中，髋部骨折导致的直接医疗费用的增加持续长达 1 年（1 年时的双重差分估计比） 2.7 [95% CI 2.1 至 3.4]；p < 0.01；连接点 1 年），1.5 至 2 年（1 年时的双差估计比 2.8 [95% CI 2.6 至 3.1]；p < 0.01；差异- 2 年时的无差异估计比 1.2 [95% CI 1.1 至 1.3]；p < 0.01；连接点 1.5 年），以及 39 个月至 5 年（1 年时的双差估计比 5.2 [95% CI 4.4]至 6.2]；p < 0.01；从零时间起 5 年的双重差分估计比为 2.1 [95% CI 1.4 至 3.1]；p < 0.01；连接点 39 个月）。

结论 

髋部骨折患者在髋部骨折前后5年内每年的直接医疗费用均高于对照组。髋部骨折导致的直接医疗费用增加持续 1.5 至 2 年，且老年患者的增加幅度更大。基于此，我们建议卫生政策应关注患者的经济和社会需求，特别重视髋部骨折后的前两年，并根据患者的年龄进行分层。

证据水平 

第二级，经济分析。