Comment on: Comorbidity burden in axial spondyloarthritis: a cluster analysis: reply

Sir, We thank Dr Vandevelde and colleagues for their interest in our study [1] and their exemplary efforts to promote and improve mental health care [2]. The burden of mental health symptoms in their patient group was high—35% with at least moderate levels of anxiety and 20% with at least moderate depression—and consistent with reports from other studies in the UK and globally [3]. These findings have direct relevance for rheumatology given emerging evidence that comorbid depression impacts assessment of axSpA and other rheumatic diseases; patients with comorbid depression may struggle to meet response criteria to continue biologic therapies, even if activity of the rheumatic disease is adequately controlled.

Mental health is inextricably linked with physical health and not limited to anxiety and depression. Using data from hospitals in Boston, USA (methods and cohort characteristics are published in this journal [4]), we show that axSpA patients with depression were also much more likely to have other mental health and substance misuse disorders (Table 1). One in three axSpA patients with depression also had alcohol dependence, one in six had drug-related disorders and nearly one in five had history of self-inflicted injuries including suicide. Physical, mental and social care improvements are desperately needed for this vulnerable group.

Table 1.

Prevalence of mental health and substance misuse comorbidities, compared between those with and without depression

	Depression n (%)	No depression n (%)	P-value
n	251	1258
Anxiety	134 (53)	96 (8)	<0.001
Suicide or self-inflicted injury	11 (4)	1 (<1)	<0.001
Alcohol dependence	83 (33)	118 (9)	<0.001
Drug related disordersa	42 (17)	34 (3)	<0.001
Opioid	30 (12)	19 (2)	<0.001
Cannabis	8 (3)	7 (1)	0.001
Cocaine and other stimulants	4 (2)	3 (<1)	0.017
Other drugs	18 (7)	10 (1)	<0.001

^aDrug-related disorders include abuse, dependence or intoxication for all drugs listed. Comorbidities were identified using International Classification of Diseases (ICD) codes.

Care provisions for mental health disorders remain limited in many countries including the USA and UK. Only a minority of people with depressive symptoms receive any treatment in the USA, with fewer still able to access treatments from specialists or modalities other than anti-depressants [5]. In the UK, only 39% of rheumatology departments had access to clinical psychology in the recent British Society for Rheumatology national audit [6]. But public attitudes and tangible investments are improving (albeit slowly). The World Health Organization set out its comprehensive Mental Health Action Plan in 2013 [7]; this was recently echoed by Public Health England’s ‘Every Mind Matters’ campaign [8]. They acknowledge the essential role of mental health in achieving overall health for all people—a fact that rheumatology is increasingly recognizing in both clinical practice and research. We hope the promising results from the Leeds clinical psychology service will inform commissioning and/or future randomized trials to improve mental health provisions.