Research Article: The association between vitamin D status and clinical events in high-risk older patients with non-ST elevation acute coronary syndrome undergoing invasive management

Date Published: June 12, 2019

Publisher: Public Library of Science

Author(s): Benjamin Beska, Danny Chan, Sophie Gu, Weiliang Qiu, Helen Mossop, Dermot Neely, Vijay Kunadian, Chiara Lazzeri.

http://doi.org/10.1371/journal.pone.0217476

Abstract

There is a higher incidence of vitamin D deficiency in older adults. This may play a plausible mechanistic role in the occurrence of increased adverse events after non-ST elevation acute coronary syndrome (NSTEACS). This study investigated whether total vitamin D levels at the time of presentation predicted adverse outcomes in older adults undergoing invasive management of NSTEACS. Of the 629 patients screened, 300 high-risk older adults with NSTEACS managed by an invasive strategy were recruited. Serum total 25-hydroxyvitamin D was measured at index presentation. The primary outcome was defined as 1-year composite of all-cause mortality, acute coronary syndrome (ACS), unplanned repeat revascularisation, significant bleeding or stroke. Mean age was 80.5±4.8 years (61.9% male). Median vitamin D level was 29.5nmol/L [interquartile range IQR 16.0–53.0 nmol/L] and was split equally by the median for analysis forming two groups: high (median vitamin D 53.0 nmol/L [IQR 40.0–75.0]) and low (16.0 nmol/L [11.0–23.0]). The primary outcome occurred in 76 patients (25.9%); 32 (21.9%) in the low group and 44 (29.9%) in the high group, p = 0.12. Multivariable analyses showed no significant difference in the primary composite outcome at 1 year between the low and high group of baseline serum vitamin D (Hazard Ratio 1.20 [95% Confidence Interval 0.72–2.0], p = 0.48). Serum total vitamin D, measured at the time of angiography, was not associated with adverse outcomes at one year in this high-risk older cohort of patients with NSTEACS undergoing invasive management.

Partial Text

Older patients have a higher incidence of adverse outcomes after acute coronary syndrome (ACS), with a 15.7 increased odds of in-hospital mortality in patients ≥85 years old compared to those <45 years old.[1, 2] Due to under-representation of this older cohort in studies of ACS, it is not clear why this population remains at increased risk.[3–5] The ageing population is likely to further increase the proportion of older patients presenting with non-ST elevation acute coronary syndrome (NSTEACS), the predominant ACS phenotype in this age group.[6] Studies involving age-appropriate biomarkers therefore are required to help understand this inequality in outcomes. Vitamin D is a hormone obtained largely through the action of ultraviolet B light on the cutaneous tissues, with sequential hydroxylation of activated skin pre-cursors by liver and kidney producing biologically active 1,25-dihydroxyvitamin D.[7] Although associated with the traditional target tissues of kidney, gut and bone and involved in inorganic ion metabolism, there is increasing evidence that low serum levels of vitamin D may be an important biomarker of an increased risk of cardiovascular disease (CVD).[7] Older patients aged ≥65 years referred to either the Freeman Hospital, Newcastle upon Tyne (Newcastle upon Tyne Hospitals NHS Foundation Trust) or James Cook University Hospital, Middlesbrough (South Tees Hospitals NHS Foundation Trust) for invasive management of NSTEACS were recruited into the ICON1 (Improve Cardiovascular Outcomes in High Risk PatieNts, Clinicaltrials.gov ID: NCT01933581) study between November 2012 and December 2015. After recruitment commencement, we focussed our recruitment on high risk older patients aged 75 and over. The ICON1 study is a multi-centre prospective cohort study that aims to determine the predictors of adverse outcomes following interventional management of NSTEACS in older patients, with an overall aim of producing a quantitative risk score for this population, the FRAIL-HEART score.[15] [16, 17] A flow diagram of recruitment to the ICON1 trial is detailed in Fig 1. 629 patients were screened. Two patients out of the 300 recruited had a non-ACS diagnosis following angiography and were excluded. Of the remaining 298 patients, 294 (98.7%) had serum total vitamin D measured. One patient was lost to 1 year follow-up, meaning the total sample available for analysis at 1 year was 293. In this older cohort of patients presenting with NSTEACS undergoing invasive management, the baseline serum vitamin D level does not predict the incidence of adverse outcomes at 1 year. Our data suggest baseline serum vitamin D level, taken at time of angiography, is not a useful biomarker to predict adverse outcomes after invasive management in this older, high-risk cohort with NSTEACS. Older patients with a prior history of MI are more likely to have a significantly lower serum vitamin D, suggesting further trials investigating vitamin D supplementation for secondary prevention in older adults are needed.   Source: http://doi.org/10.1371/journal.pone.0217476

 

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