Slow walking speed predicts mortality in older adults with CV, neuropsychiatric multimorbidity

Functional impairment, as indicated by slow walking speed, appears to be a strong predictor of mortality in older adults with cardiovascular (CV) and neuropsychiatric multimorbidity, according to a study.

“[O]ur study suggests that slow walking speed … provides additional prognostic information in terms of mortality, beyond the number of CV and neuropsychiatric diseases, independently of potential confounders, and particularly in the short-term period,” the researchers said.

A total of 3,241 participants (aged ≥60 years) in the Swedish National study of Aging and Care in Kungsholmen were included in this cohort study. Number of CV and neuropsychiatric diseases was categorized as 0, 1 or ≥2. Functional impairment was defined as walking speed of <0.8 m/s. Information on 3- and 5-year mortality was obtained from death certificates.

The researchers estimated hazard ratios (HRs) from Cox models (all-cause mortality) and Fine-Gray competing risk models (CV and non-CV mortality).

The multivariable-adjusted HRs of all-cause mortality after 3 years were 1.88 (95 percent confidence interval [CI], 1.29–2.74) for people with functional impairment combined with 0 CV diseases, 3.85 (95 percent CI, 2.60–5.70) with 1 CV disease and 5.11 (95 percent CI, 3.45–7.78) with ≥2 CV diseases compared with participants with preserved walking speed and without either CV or neuropsychiatric diseases. [Am J Med 2019;132:1207-1215.e6]

The corresponding HRs for those with 0, 1 and ≥2 neuropsychiatric diseases were 2.88 (95 percent CI, 2.03–4.08), 3.36 (2.31–4.89) and 3.68 (2.43–5.59).

Functional impairment among people with ≥2 CV or neuropsychiatric diseases correlated with an excess risk for 3-year all-cause mortality of 18 and 17 per 100 person-years, respectively, as compared to those without functional impairment. At 5 years, the association between the number of CV diseases and mortality ensued independent of functional impairment.

“In agreement with recent guidelines on multimorbidity, our findings support the simultaneous assessment of clinical and functional parameters that facilitates the identification of patients’ clinical priorities, of optimal drug treatment, and better counselling,” the researchers said.

Significant associations between multimorbidity and mortality were also reported in earlier studies, they added. Of note, a multiplicative interaction exists among cardiometabolic diseases, indicating that these diseases when combined exert a negative impact on survival beyond the sum of their individual effects. [JAMA 2015;314:52-60]

Functional status has also been shown to drive the prognosis of an individual with several risk factors and chronic diseases and following invasive procedures such as heart surgery. [J Gerontol A Biol Sci Med Sci 2016;71:221-227; JACC Heart Fail 2016;4:289-298; BMC Geriatr 2017;17:294; Arch Intern Med 2012;172:1162-1168; Canadian Respir J 2015;22:225-229; Am J Kidney Dis 2015;66:297-304]

The researchers, however, noted that several factors could influence walking speed and must be considered when interpreting their results. Slow walking speed, according to them, may derive from acute or chronic systemic conditions (eg, fever or malnutrition), impairment of a single organ (eg, hip osteoarthritis), or mental conditions (eg, depression). It can also be a symptom of a specific disease (eg, Parkinson’s disease).

“The adoption of a simple and easy-to-use measure of functional impairment such as walking speed may help healthcare professionals in identifying older people affected by specific groups of chronic diseases that have similar needs, health trajectories and prognoses,” the researchers said.