The hidden comorbidities

Author: Dr Kieran Walsh, Clinical Director, BMJ 

When I talk to doctors about patients with multiple conditions, they all agree that it is a problem. When I ask what conditions are a particular problem, they come up with a list of usual suspects. They mention patients with COPD, heart failure and diabetes mellitus. Or patients with stroke, hypertension and ischemic heart disease. Or another overlapping cluster of chronic kidney disease, diabetes and hypertension. But only rarely do they spontaneously mention mental health conditions. When I suggest depression or dementia, they immediately agree that these are a problem also. But they don’t get as much air time as the other comorbidities.


Comorbid mental health conditions can have a real impact on clinical outcomes

This is unfortunate as comorbid mental health conditions can have a real impact on clinical outcomes. There are many examples of this. Frayne et al showed that patients with diabetes and co-existing mental health conditions were less likely to receive the care that they should. (1) They were less likely to receive haemoglobin A1C tests, cholesterol tests, and eye examinations. This is worrying as these are the basics of diabetes care. The mental health conditions included depression, anxiety, psychosis, mania, substance use disorder, and personality disorder. In another study, Braunstein et al showed that patients with heart failure and depression had a higher risk of hospitalisation and mortality. (2) There is also evidence that patients with COPD and depression have impaired quality of life and reduced adherence to treatment. (3) They are also more likely to suffer from fatigue.

Healthcare professionals find the management of comorbidities difficult

BMJ Best Practice is the clinical decision support tool of the BMJ. When we speak to users of the tool, they commonly state that they find management of comorbidities difficult. They worry that by treating one condition they might make another condition worse. And this includes mental health conditions. They need guidance on common problems, such as: how steroids can worsen symptoms of depression; or how antidepressants can exacerbate hyponatremia in a patient taking diuretics; or how sedative antidepressants may precipitate respiratory depression in a patient with COPD. Clearly it is imperative that patients with coexistent mental and physical health disorders receive adequate treatment for their mental disorder or physical disorder or both disorders. BMJ Best Practice is working on a solution for this, and we would be delighted to hear from you if you had suggestions on how we could help. Please email on


Try the new Comorbidities tool from BMJ Best Practice

The Comorbidities tool is the only point of care tool that supports the management of the whole patient by including guidance on the treatment of a patient’s acute condition alongside their pre-existing comorbidities.

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1. Frayne SM, Halanych JH, Miller DR, Wang F, Lin H, Pogach L, et al. Disparities in diabetes care: impact of mental illness. Arch Intern Med 2005;165(22):2631–2638.
2. Braunstein JB, Anderson GF, Gerstenlith G, Weller W, Niefeld M, Herbert R, et al. Non-cardiac comorbidity increases preventable hospitalizations and mortality among Medicare beneficiaries with chronic heart failure. J Am Coll Cardiol 2003;42(7):1226–1233.
3. Yohannes AM, Alexopoulos GS. Depression and anxiety in patients with COPD. Eur Respir Rev. 2014 Sep;23(133):345-9.


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Competing interests
Kieran Walsh works for BMJ which produces the clinical decision support tool BMJ Best Practice.