Division of Nephrology and Hypertension, Kaiser Permanente Los Angeles Medical Center, Los Angeles, California, USA.
Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, California, USA.
Intern Med J. 2020 Sep;50(9):1100-1108. doi: 10.1111/imj.14684.
Falls and hip fractures among older people are associated with high morbidity and mortality. Hyponatraemia may be a risk for falls/hip fractures, but the effect of hyponatraemia duration is not well understood.
To evaluate individuals with periods of sub-acute and chronic hyponatraemia on subsequent risk for serious falls and/or hip fractures.
Retrospective cohort study in the period 1 January 1998 to 14 June 2016 within an integrated health system of individuals aged ≥55 years with ≥2 outpatient serum sodium measurements. Hyponatraemia was defined as sodium <135 mEq/L with sub-acute (<30 days) and chronic (≥30 days) analysed as a time-dependent exposure. Multivariable Cox proportional-hazards modelling was used to estimate hazard ratios (HR) for serious falls/hip fractures based on sodium category.
Among 1 062 647 individuals totalling 9 762 305 sodium measurements, 96 096 serious falls/hip fracture events occurred. Incidence (per-1000-person-years) of serious falls/hip fractures were 11.5, 27.9 and 19.8 for normonatraemia, sub-acute and chronic hyponatraemia. Any hyponatraemia duration compared to normonatraemia had a serious falls/hip fractures HR (95%CI) of 1.18 (1.15, 1.22), with sub-acute and chronic hyponatraemia having HR of 1.38 (1.33, 1.42) and 0.91 (0.87, 0.95), respectively. Examined separately, the serious falls HR was 1.37 (1.32, 1.42) and 0.92 (0.88, 0.96) in sub-acute and chronic hyponatraemia, respectively. Hip fracture HR were 1.52 (1.42, 1.62) and 1.00 (0.92, 1.08) for sub-acute and chronic hyponatraemia, respectively, compared to normonatraemia.
Our findings suggest that early/sub-acute hyponatraemia appears more vulnerable and associated with serious falls/hip fractures. Whether hyponatraemia is a marker of frailty or a modifiable risk factor for falls remains to be determined.
老年人的跌倒和髋部骨折与高发病率和死亡率有关。低钠血症可能是跌倒/髋部骨折的一个风险因素，但低钠血症持续时间的影响尚不清楚。
评估亚急性和慢性低钠血症患者随后发生严重跌倒和/或髋部骨折的风险。
这是一项回顾性队列研究，于 1998 年 1 月 1 日至 2016 年 6 月 14 日期间，在一个综合健康系统中，纳入了年龄≥55 岁且有≥2 次门诊血清钠测量值的患者。低钠血症定义为血清钠<135 mEq/L，亚急性（<30 天）和慢性（≥30 天）分析为时间依赖性暴露。多变量 Cox 比例风险模型用于估计根据钠分类的严重跌倒/髋部骨折的危险比（HR）。
在 1062647 名患者中，共发生了 9762305 次血清钠测量，有 96096 例严重跌倒/髋部骨折事件。正常钠血症、亚急性和慢性低钠血症的严重跌倒/髋部骨折发生率（每 1000 人年）分别为 11.5、27.9 和 19.8。与正常钠血症相比，任何低钠血症持续时间均有严重跌倒/髋部骨折的 HR（95%CI）为 1.18（1.15，1.22），亚急性和慢性低钠血症的 HR 分别为 1.38（1.33，1.42）和 0.91（0.87，0.95）。单独检查时，亚急性低钠血症的严重跌倒 HR 为 1.37（1.32，1.42），慢性低钠血症的 HR 为 0.92（0.88，0.96）。与正常钠血症相比，亚急性和慢性低钠血症的髋部骨折 HR 分别为 1.52（1.42，1.62）和 1.00（0.92，1.08）。
我们的研究结果表明，早期/亚急性低钠血症似乎更脆弱，与严重跌倒/髋部骨折有关。低钠血症是脆弱的标志还是跌倒的可改变风险因素仍有待确定。
