Almost three quarters of Irish adults have two or more medical conditions

A study from The Irish Longitudinal Study on Ageing (TILDA) published in the Nature Journal Scientific Reports has shown, for the first time, that almost three quarters of Irish adults have two or more chronic or cardiovascular medical conditions at the same time (multimorbidity).

Furthermore, just over one-in-three have four or more simultaneous medical conditions. The findings of the study identify implications for public health policy, public health awareness and for improving management of disorders in clinical assessments.

Researchers from TILDA, Trinity College Dublin, used novel machine learning methods to identify patterns and networks of common disease co-occurrences in 31 medical conditions present in 6,101 Irish adults aged 50+.

Among their main findings were the significant differences shown in the prevalence of 22 out of 31 medical conditions between males and females. Females had a more complex network of disease associations than males with medical conditions such as osteoporosis, arthritis, urinary incontinence and thyroid illnesses being far more prevalent in females than males.

It was also found that many cardiovascular diseases (hypertension, angina, high cholesterol, heart failure) and related conditions such as diabetes and obesity were highly over-represented in Irish males. For both sexes, hypertension and high cholesterol was the most common disease to co-occur, affecting over a quarter of adults.

For males, combinations of hypertension, high cholesterol, arthritis and obesity formed the most common disease combinations whereas for females the most common disease combinations also included urinary incontinence, osteoporosis and cataracts.

Dr Belinda Hernández, lead author and a TILDA researcher, commented: “The study of multimorbidity is significant for public health. We have shown that almost three in every four older Irish adults suffer from multimorbidity. Multimorbidity has previously been shown to increase the likelihood of functional and physical decline as well as impacting the quality of life and increasing both mortality and healthcare costs. In our study, we identified 639 combinations of diseases which occur more often than would be expected by random chance in older Irish adults.”

Explaining the importance of this research, Dr Hernández continued: “We hope that this information can be used to guide clinicians in deciding which diseases should be screened for or incorporated into their comprehensive clinical assessments. This information may be used to anticipate future diseases that patients are likely to suffer, given their existing list of medical conditions. Thus, it will help clinicians develop intervention and prevention strategies to improve care.”

Prof Rose Anne Kenny, Principal Investigator of TILDA, Director of the Falls and Syncope Unit at St James Hospital, Dublin and senior author on the study, commented: “Multimorbidity is a major issue affecting our public health. Multimorbidity presents significant challenges to comprehensive assessment of mature adults and drug interactions.

“Awareness of combinations will improve management and better ensure that disorders are not dealt with in isolation, such as treating osteoporosis without assessment and management of other cooccurring disorders such as thyroid, cardiovascular and arthritic disorders.”

Prof Kenny said the findings can be used to improve guidelines for clinical assessments of Irish adults and to inform national health policy and care pathways.

“One of the main things we uncovered is that the combination and number of medical conditions present in Irish adults are very mixed (heterogeneous). This highlights the importance of ensuring that we treat people not diseases and that we take account of all of the information regarding patients’ physical and mental health and move away from a system of treating diseases in isolation.”

Future research is underway within TILDA to benchmark and compare disease patterns for multimorbidity in Ireland against the United States, Canada and England. Other studies in TILDA researchers are also using the information from this study to provide insights into the underlying biological mechanisms which could explain such disease co-occurrences and the TILDA team are investigating the role of inflammation, immune responses and metabolic systems in multimorbidity and ageing.

The research article, published in the Nature Journal Scientific Reports is available here: www.nature.com/articles/s41598-019-51135-7

The Irish Longitudinal study on Ageing is funded by the Department of Health, the Atlantic Philanthropies and Irish Life. This study was funded by the Health Research Board (HRB).