Naval Medical Center Portsmouth, Portsmouth, VA, USA.
Captain James A. Lovell Federal Health Care Center, North Chicago, IL, USA.
Clin Orthop Relat Res. 2022 Nov 1;480(11):2111-2119. doi: 10.1097/CORR.0000000000002304. Epub 2022 Jun 28.
Lower extremity stress fractures result in lost time from work and sport and incur costs in the military when they occur in service members. Hypovitaminosis D has been identified as key risk factor in these injuries. An estimated 33% to 90% of collegiate and professional athletes have deficient vitamin D levels. Other branches of the United States military have evaluated the risk factors for stress fractures during basic training, including vitamin D deficiency. To the best of our knowledge, a study evaluating the correlation between these injuries and vitamin D deficiency in US Navy recruits and a cost analysis of these injuries has not been performed. Cutbacks in military medical staffing mean more active-duty personnel are being deferred for care to civilian providers. Consequently, data that previously were only pertinent to military medical providers have now expanded to the nonmilitary medical community.
QUESTIONS/PURPOSES: We therefore asked: (1) What proportion of US Navy recruits experience symptomatic lower extremity stress fractures, and what proportion of those recruits had hypovitaminosis vitamin D on laboratory testing? (2) What are the rehabilitation costs involved in the treatment of lower extremity stress fractures, including the associated costs of lost training time? (3) Is there a cost difference in the treatment of stress fractures between recruits with lower extremity stress fractures who have vitamin D deficiency and those without vitamin D deficiency?
We retrospectively evaluated the electronic medical record at Naval Recruit Training Command in Great Lakes, IL, USA, of all active-duty males and females trained from 2009 until 2015. We used ICD-9 and ICD-10 diagnosis codes to identify those diagnosed with symptomatic lower extremity stress fractures. Data collected included geographic region of birth, preexisting vitamin D deficiency, vitamin D level at the time of diagnosis, medical history, BMI, age, sex, self-reported race or ethnicity, hospitalization days, days lost from training, and the number of physical therapy, primary care, and specialty visits. To ascertain the proportion of recruits who developed symptomatic stress fractures, we divided the number of recruits who were diagnosed with a stress fracture by the total number who trained over that span of time, which was 204,774 individuals. During the span of this study, 45% (494 of 1098) of recruits diagnosed with a symptomatic stress fracture were female and 55% (604 of 1098) were male, with a mean ± SD age of 24 ± 4 years. We defined hypovitaminosis D as a vitamin D level lower than 40 ng/mL. Levels less than 40 ng/mL were defined as low normal and levels less than 30 ng/mL as deficient. Vitamin D levels were obtained at the discretion of the individual treating provider without standardization of protocol. Cost was defined as physical therapy visits, primary care visits, orthopaedic visits, diagnostic imaging costs, laboratory costs, hospitalizations, if applicable, and days lost from training. Diagnostic studies and laboratory tests were incorporated as indirect costs into initial and follow-up physical therapy visits. Evaluation and management code fee schedules for initial visits and follow-up visits were used as direct costs. We obtained these data from the Centers for Medicare & Medicaid Services website. Per capita cost was calculated by taking the total cost and dividing it by the study population. Days lost from training is based on a standardized government military salary of recruits to include room and board.
We found that 0.5% (1098 of 204,774) of recruits developed a symptomatic lower extremity stress fracture. Of the recruits who had vitamin D levels drawn at the time of stress fracture, 95% (416 of 437 [95% confidence interval (CI) 94% to 98%]; p > 0.99) had hypovitaminosis D (≤ 40 ng/mL) and 82% (360 of 437 [95% CI 79% to 86%]; p > 0.99) had deficient levels (≤ 30 ng/mL) on laboratory testing, when evaluated. The total treatment cost was USD 9506 per recruit. Days lost in training was a median of 56 days (4 to 108) for a per capita cost of USD 5447 per recruit. Recruits with deficient vitamin D levels (levels ≤ 30 ng/mL) incurred more physical therapy treatment costs than did those with low-normal vitamin D levels (levels 31 to 40 ng/mL) (mean difference USD 965 [95% CI 2 to 1928]; p = 0.049).
The cost of lost training and rehabilitation associated with symptomatic lower extremity stress fractures represents a major financial burden. Screening for and treatment of vitamin D deficiencies before recruit training could offer a cost-effective solution to decreasing the stress fracture risk. Recognition and treatment of these deficiencies has a role beyond the military, as hypovitaminosis and stress fractures are common in collegiate or professional athletes.
Level III, prognostic study.
下肢应力性骨折会导致士兵在服役期间因工作和运动而损失时间，并产生医疗费用。维生素 D 缺乏已被确定为这些损伤的关键风险因素。估计有 33%至 90%的大学生和职业运动员维生素 D 水平不足。美国其他军种已经评估了基础训练期间发生应力性骨折的风险因素，包括维生素 D 缺乏。据我们所知，目前还没有一项研究评估美国海军新兵中这些损伤与维生素 D 缺乏之间的相关性，也没有对这些损伤的成本分析。军队医务人员的削减意味着更多的现役人员因护理而被推迟到民用提供者。因此，以前仅与军队医务人员相关的数据现在已经扩展到非军队医务人员社区。
问题/目的：我们因此提出以下问题：(1) 有多少美国海军新兵出现下肢症状性应力性骨折，有多少新兵在实验室检测中出现维生素 D 缺乏症？(2) 下肢应力性骨折治疗的康复费用是多少，包括与培训时间损失相关的费用？(3) 下肢应力性骨折的新兵中，维生素 D 缺乏症与非维生素 D 缺乏症患者的治疗费用是否存在差异？
我们回顾性评估了美国伊利诺伊州大湖海军新兵训练营的电子病历，时间范围为 2009 年至 2015 年。我们使用 ICD-9 和 ICD-10 诊断代码来识别那些被诊断为下肢症状性应力性骨折的患者。收集的数据包括出生地的地理位置、预先存在的维生素 D 缺乏症、诊断时的维生素 D 水平、病史、体重指数、年龄、性别、自我报告的种族或族裔、住院天数、训练损失天数以及物理治疗、初级保健和专科就诊的次数。为了确定新兵中出现症状性应力性骨折的比例，我们将被诊断为应力性骨折的新兵人数除以在这段时间内接受训练的新兵总人数，即 204774 人。在这项研究期间，45%(494/1098)的症状性应力性骨折新兵为女性，55%(604/1098)为男性，平均年龄为 24±4 岁。我们将维生素 D 缺乏定义为维生素 D 水平低于 40ng/ml。低于 40ng/ml 的被定义为低正常，低于 30ng/ml 的被定义为缺乏。维生素 D 水平是由个别治疗提供者根据自己的判断获得的，没有标准化的方案。费用定义为物理治疗就诊、初级保健就诊、矫形就诊、诊断成像费用、实验室费用、住院费用(如果适用)和训练损失天数。诊断研究和实验室测试作为间接费用纳入初始和随访物理治疗就诊。初始就诊和随访就诊的评估和管理代码费用表被用作直接费用。我们从医疗保险和医疗补助服务中心网站获得这些数据。人均费用是通过将总费用除以研究人群来计算的。训练损失天数基于新兵的标准化政府军薪，包括食宿。
我们发现，0.5%(1098/204774)的新兵出现了下肢症状性应力性骨折。在有应力性骨折时进行维生素 D 水平检测的新兵中，95%(416/437[95%置信区间(CI)94%至 98%]；p>0.99)患有维生素 D 缺乏症(≤40ng/ml)，82%(360/437[95%CI 79%至 86%]；p>0.99)患有缺乏症(≤30ng/ml)。新兵的治疗总费用为每人 9506 美元。训练损失的天数中位数为 56 天(4 至 108)，每人的费用为 5447 美元。维生素 D 缺乏症(水平≤30ng/ml)新兵的物理治疗治疗费用高于维生素 D 水平正常(31 至 40ng/ml)新兵(平均差异 965 美元[95%CI 2 至 1928]；p=0.049)。
与下肢症状性应力性骨折相关的培训和康复费用是一项重大的财务负担。在新兵训练前筛查和治疗维生素 D 缺乏症可能是降低应力性骨折风险的一种具有成本效益的方法。这些缺陷的认识和治疗不仅在军队中具有重要意义，而且在大学生或职业运动员中，维生素 D 缺乏症和应力性骨折也很常见。
III 级，预后研究。
