Recognition of Hyponatremia As a Risk Factor for Hip Fractures in Older Persons

THE EFFECTS OF HYPONATREMIA ON BONE DENSITY AND FRACTURES: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: Hyponatremia decreases bone mineral density and is a major risk factor for fragility fractures. Objectives of our systematic review and meta-analysis were to analyze the overall effects of hyponatremia on bone fractures, osteoporosis, and mortality. Methods: We extracted data from Medline, Cochrane Central, and EMBASE 1960-2017 and conference abstracts from 2007-2017. We included studies with data on serum sodium, fractures, bone density, or diagnoses of osteoporosis. Studies were independently reviewed by two authors and assessed for bias using the Newcastle-Ottawa scale. Random effect models meta-analysis was used when at least three studies reported the same outcome measures. We reported summary odds ratios (ORs) and 95% confidence intervals (CIs). Results: We included 26 studies for qualitative analysis. Fifteen studies were included in the meta-analysis to evaluate the effects of hyponatremia on fractures, four studies for bone mineral density changes, and six for mortality. Hyponatremia increased the odds of fractures at all sites (summary OR, 2.34 [95% CI, 1.86, 2.96]. There was an increase in the odds of osteoporosis (summary OR, 2.67 [95% CI, 2.07, 3.43]). Mortality risk among the included studies remained high (summary OR, 1.31 [95% CI, 1.16, 1.47]). Conclusion: Our meta-analysis confirms a statistically significant association of hyponatremia with bone fractures and osteoporosis along with higher mortality. Long-term prospective studies evaluating the impact of correcting hyponatremia on bone health, fractures, and mortality are required. Abbreviations: AVP = arginine vasopressin; CI = confidence interval; CKD = chronic kidney disease; OR = odds ratio; SIADH = syndrome of inappropriate antidiuretic hormone.

Hyponatremia, falls and bone fractures: A systematic review and meta-analysis

OBJECTIVE

To perform a meta-analysis based on published studies that compared falls and bone fractures between patients with and without hyponatremia.

CONTEXT

There is evidence suggesting that hyponatremia is associated with an increased risk of falls and bone fractures.

DESIGN

An extensive Medline, Embase and Cochrane search was performed to retrieve all studies published up to, 30 April 2017, using the following words: "hyponatremia" or "hyponatraemia" AND "falls" and "bone fractures." A meta-analysis was performed including all studies comparing falls and bone fractures in subjects with or without hyponatremia.

PATIENTS AND RESULTS

Of 216 retrieved articles, 15 studies satisfied inclusion criteria encompassing a total of 51 879 patients, of whom 2329 were hyponatremic. Across all studies, hyponatremia was associated with a significantly increased risk of falls (MH-OR = 2.14[1.71; 2.67]. This result was confirmed when only hospitalized patients were considered (MH-OR = 2.44 [1.97; 3.02]). A meta-regression analysis showed that the hyponatremia-related risk of falls was higher in those studies considering a lower serum [Na+ ] cut-off to define hyponatremia. Interestingly, the estimated risk of falls related to hyponatremia was already significantly higher when a serum [Na+ ] cut-off of 135 mmol/L was considered (MH-OR = 1.26[1.23;1.29]). The presence of hyponatremia was also associated with a higher risk of fractures, particularly hip fractures (MH-OR = 2.00[1.43;2.81]).

CONCLUSIONS

This study confirms that hyponatremia is associated with an increased risk of falls and bone fractures. The clinical, social and economic relevance of such association is strengthened by the increased incidence of hyponatremia in older people.