Smoking and potentially preventable hospitalisation: The benefit of smoking cessation in older ages
Introduction
Preventable hospitalisations are those that might be avoided through prevention and management in primary care, and rates of these admissions are used internationally as an indicator of health system performance (Jorm et al., 2012). Preventable hospitalisations account for around 10% of total hospital stays and total hospital expenditure (Stranges and Stocks, 2008), and reducing them is a priority for health systems worldwide (Muenchberger and Kendall, 2010).
The chronic conditions included in commonly used definitions of preventable hospitalisation include congestive heart failure (CHF), diabetes complications, chronic obstructive pulmonary disease (COPD) and angina, all of which are smoking-related. Accordingly, there is clear potential to reduce the rate of these hospitalisations through interventions to promote smoking cessation (Jackson et al., 2001). The majority of preventable hospitalisations for chronic conditions occur among people aged 65 years and over (Stranges and Stocks, 2008). While it has been clearly demonstrated that quitting smoking at age 60 years or older reduces the risk of mortality from all causes and many smoking-related causes (Gellert et al., 2012, He et al., 2014), few population-based studies have quantified the benefits of “late” quitting for preventable hospitalisation outcomes. Existing studies of the relationship between smoking and preventable hospitalisation in older populations have been restricted to specific patient groups (Godtfredsen et al., 2002, Shah et al., 2010), have presented combined mortality and morbidity endpoints (Gellert et al., 2013b), or have not stratified according to age at quitting (Baumeister et al., 2007).
In this study, data from a large prospective cohort of Australian men and women aged 45 years and over, linked with hospital morbidity data were used to: (1) quantify the effects of smoking on risk of preventable hospitalisation (expressed both as hazard ratios [HRs] and risk advancement periods [RAP]) for CHF, diabetes complications, COPD and angina; (2) investigate the contributions of smoking duration and smoking intensity to these risks; and (3) investigate the impact of quitting smoking at older ages on risk of preventable hospitalisation.
Section snippets
Participants
This analysis was part of the Assessing Preventable Hospitalisation InDicators (APHID) study (Jorm et al., 2012). APHID uses linked survey and administrative data for participants in the Sax Institute's 45 and Up Study, a prospective cohort of 267,091 men and women aged 45 years and over and resident in New South Wales (NSW), Australia (Banks et al., 2008). Participants were randomly sampled from the database of the national health insurance scheme (Medicare Australia). Participants entered the
Results
Of the 267,091 participants in the 45 and Up Study, 60 participants were excluded because of missing date of study entry and a further 21 were excluded because of possible inconsistent linkage, leaving 267,010 eligible participants included in this analysis. The mean age of participants was 63 years (standard deviation 11 years). Women comprised nearly 54% of the cohort.
Over an average of 2.7 years follow-up (interquartile range: 2.3–2.9 years), 11,035 (4.1%) participants were admitted to
Discussion
In this large population-based cohort of Australian men and women aged 45 years and over, we found that cigarette smoking substantially increased the risk of preventable hospitalisation for chronic conditions. Current smoking increased hospitalisation risk almost 7-fold for COPD, and by 25–41% for diabetes complications, angina and CHF. Prolonged smoking duration was associated with increased risk of hospitalisation, and this was exacerbated by heavy smoking intensity. For example, among
Role of funding source
The study was funded by a National Health and Medical Research Council Partnership Project Grant (#1036858) and by partner agencies the Australian Commission on Safety and Quality in Health Care, the Agency for Clinical Innovation and the NSW Bureau of Health Information. The funders play no role in approving the publications.
Contributors
BT conducted the data analyses and drafted the manuscript. MF extracted data for analysis, assisted with statistical methods and data presentation, and reviewed and edited the manuscript. LJ conceived, designed and managed the study, obtained funding, reviewed and edited the manuscript and provided overall supervision. All authors reviewed and approved the final manuscript.
Conflict of interest
The authors have declared that no competing interests exist.
Acknowledgements
The APHID investigator team comprises Louisa Jorm, Alastair Leyland, Fiona Blyth, Robert Elliot, Kirsty Douglas, Sally Redman, Marjon van der Pol, Michael Falster, Bich Tran, Neville Board, Danielle Butler, Douglas Lincoln, Sanja Lujic, Damilola Olajide, Deborah Randall, Kim Sutherland and Diane Watson.
This research was completed using data collected through the 45 and Up Study (www.saxinstitute.org.au). The 45 and Up Study is managed by the Sax Institute in collaboration with major partner
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