Anxiety and chronic illness

Anxiety and cardiovascular disease have one of the best-documented links. Roest and colleagues' 2010 meta-analysis of prospective post-myocardial-infarction cohorts found that patients with elevated anxiety had roughly 1.4 times the risk of subsequent cardiac events and mortality compared with non-anxious patients, adjusting for known predictors. Panic disorder in particular has been studied as a driver of emergency-department utilization (see the report on panic and emergency care). Mechanistic candidates include altered autonomic function, inflammation, and behavioral pathways such as adherence to prevention regimens.

Diabetes distress, a construct related to but distinct from generalized anxiety, is common in adults living with diabetes. Meta-analyses find elevated rates of anxiety disorders in adults with type 1 and type 2 diabetes compared with the general population, and anxiety is independently associated with poorer glycemic control in longitudinal studies. Screening for anxiety and depression is now embedded in several US diabetes care standards.

Anxiety is unusually common in COPD, in part because the physical experience of breathlessness overlaps directly with the physical experience of panic. Meta-analyses estimate clinically significant anxiety in roughly a third of COPD patients. Anxiety in COPD is associated with higher rates of exacerbation-related hospitalization and lower completion of pulmonary rehabilitation, both of which affect long-term outcomes.

Anxiety around cancer diagnosis, treatment, and follow-up is common and, at moderate levels, appropriate to the situation. Distinguishing clinically significant anxiety disorders from adjustment reactions is one of the practical challenges in oncology psychology. NCCN's distress-thermometer approach and disease-specific psycho-oncology guidelines have moved toward routine screening, and integrated psycho-oncology services are increasingly standard at cancer centers.

Anxiety and chronic pain co-occur at rates well above chance and reinforce each other prospectively in cohort studies. Bair and colleagues' systematic reviews consistently find bidirectional prospective associations. The overlap complicates both diagnosis (pain and anxiety share physical features) and treatment (some medications used for one also affect the other, with a mix of helpful and complicating results).

The associations are consistent across large observational datasets. What the observational data cannot prove is that treating anxiety, on its own, changes the medical outcome. Some randomized trials of collaborative care for anxiety plus depression in chronic disease clinics have found benefits on symptom measures and functional outcomes; medical-outcome effects are more modest and less consistent.

Anxiety occurs more often in people with chronic medical conditions than in the general population. The pattern has been documented for cardiovascular disease, diabetes, chronic obstructive pulmonary disease, cancer, and chronic pain, among others. The elevated prevalence is consistent enough across conditions that the link isn't specific to any one illness. Point-prevalence of clinically significant anxiety in these populations commonly falls in the 20 to 40 percent range, several times the general-population rate.

Several mechanisms likely contribute, and they aren't mutually exclusive. A serious diagnosis and the daily burden of managing a chronic illness are themselves significant stressors. Some conditions and some medications produce physical symptoms that overlap with anxiety, such as a racing heart or breathlessness. And shared biological pathways, including inflammation and stress-system activity, have been studied as common ground between anxiety and several chronic diseases.

Comorbid anxiety matters for the medical condition, not only for mental health. Roest and colleagues' 2010 meta-analysis of post-myocardial-infarction cohorts found that anxiety was associated with increased risk of subsequent cardiac events. Anxiety is associated with lower adherence to medical treatment, higher health-care use, and, in some conditions, worse medical outcomes. This is why screening for anxiety, typically with the GAD-7, is increasingly recommended within the care of several chronic diseases.

The association is well established. The direction of cause and the mechanism vary by condition and are still being studied. Symptom overlap between anxiety and physical illness makes precise measurement difficult.

The medical significance of comorbid anxiety differs by condition; anxiety after myocardial infarction, for example, has stronger prognostic data than anxiety in some other chronic conditions.