Non-invasive clinical and physical signs, symptoms and indications for identification of impending and current water-loss dehydration in older people: a diagnostic accuracy systematic review

Introduction
Water-loss dehydration is common in older people and associated with excess morbidity and mortality, but it is unclear which signs/symptoms identify dehydration in this group. Diagnostic accuracy of possible clinical and physical signs, symptoms and indications of water-loss dehydration in older people were assessed against serum osmolality or weight change (reference standards)1.

Methods
Structured searches were run in seven databases. Assessment of inclusion, data extraction and assessment of validity were duplicated. Where data sets included index tests and a reference standard, but were not analysed for diagnostic accuracy, reviewers analysed the data. Diagnostic accuracy of each sign, symptom or indicator was assessed against the best reference standard, and data presented in sensitivity and specificity forest plots. Pre-set minimum sensitivity was 60%, specificity 75%. Secondary analyses created receiver operating characteristic (ROC) curves for continuous tests.

Results
We included 24 studies (3 using published data, 21 analysing raw data sets) reporting 67 tests. No index tests were reproducibly usefully diagnostic of water-loss dehydration in older people, but promising signs/symptoms, which need further assessment, are shown in the table. There was sufficient evidence to suggest that some signs/symptoms should not be used to indicate dehydration (table).

Conclusions
No single sign/symptom was diagnostic of water-loss dehydration in older people. Individual signs should not be used in this population to indicate dehydration as they will miss many with dehydration, and wrongly label those adequately hydrated. Promising signs identified by this review need to be further assessed.

1. Hooper L et al, Cochrane Library (protocol) 2011: CD009647-DOI:1002/14651858.