Co-morbid condition as an important factor influencing depression treatment

Abstract

There are different factors influencing the treatment of depression. An important factor is co-morbidity. We made an analysis of depression treatment within general practice in Estonia as part of the PREDICT study in 2003–2005. The study group consisted of consecutive patients (n=1094), aged 18–75 years, who sought consultation from their family doctor. We found that more antidepressants, anxiolytics, and hypnotics were prescribed to patients with co-morbid mental disorder (odds ratio [95% confidence interval] 5.49 [3.61–8.40], 8.38 [5.33–13.18], and 4.02 [2.30–7.02], respectively) compared to those patients who did not have this disorder.

• Depression
• co-morbid condition

In a recent issue of European Journal of General Practice, an excellent article, “Depressed and co-morbid condition: More psychotropics prescribed!” by Smolders et al. [1], discussed the association between treatment of depression and co-morbidity. The authors found that more psychotropic drugs were prescribed to depressed patients with somatic or psychiatric co-morbidity than to patients without it. This is an interesting fact. We wish to expand these findings by adding our results.

We made an analysis of depression treatment within general practice in Estonia as part of the PREDICT (Prediction of Future Episodes of Depression in Primary Medical Care: Evaluation of Risk Factor Profile) study in 2003–2005. Our study group consisted of consecutive patients (n=1094), aged 18–75 years, who sought consultation from their family doctor [2]. The occurrence of depression was assessed by using the Composite International Diagnostic Interview (CIDI), version 2.1, which provides a 6-month depression diagnosis according to the International Classification of Diseases (ICD-10) [3]. We also analysed the medical records of all patients in terms of their co-morbidity and treatment of depression. Statistical analyses (descriptive statistics and logistic regression analysis) were performed by using the SPSS Base System for Windows 10.0.

The results are given in Table I. We found that 377 (35%) of the patients were depressed. Most of the depressed patients, i.e., 337 (89%), had a co-morbid condition. Antidepressants were taken by 33%, anxiolytics by 24%, and hypnotics by 11% of the depressed patients. More antidepressants, anxiolytics, and hypnotics were prescribed to patients with co-morbid mental disorder (odds ratio [OR] (95% confidence interval [CI]) 5.49 (3.61–8.40), 8.38 (5.33–13.18), and 4.02 (2.30–7.02), respectively) compared to those patients who did not have this disorder. Of somatic diseases, the neurological (OR 1.99, 95% CI 1.20–3.30), urological (OR 1.55, 95% CI 1.01–2.40), and cardiovascular (OR 1.48, 95% CI 1.04–2.11) diseases were also associated with high antidepressant use. Anxiolytics were more often used in patients with cardiovascular (OR 4.01, 95% CI 2.67–6.01), neurological (OR 2.73, 95% CI 1.56–4.76), digestive (OR 1.97, 95% CI 1.30–3.01), and musculoskeletal (OR 1.50, 95% CI 1.02–2.20) diseases. Hypnotics were more often prescribed to patients with malignant (OR 3.03, 95% CI 1.16–7.90), endocrinological (OR 2.80, 95% CI 1.57–4.98), urological (OR 2.39, 95% CI 1.33–4.28), and musculoskeletal (OR 1.86, 95% CI 1.08–3.22) diseases.

Table I.  Co-morbidity associated with psychotropic medication use.

	OR (95% CI)
Concomitant disease	Antidepressants	Anxiolytics	Hypnotics
Infectious disease	1.20 (0.75–1.93)	1.13 (0.65–1.97)	1.14 (0.53–2.43)
Malignant disease	1.38 (0.63–3.03)	1.95 (0.87–4.39)	3.03 (1.16–7.90)
Ophthalmologic disease	2.35 (0.90–6.13)	0.64 (0.16–2.62)	0.43 (0.05–3.66)
Ear disease	1.28 (0.68–2.42)	0.81 (0.37–1.76)	1.08 (0.39–3.01)
Injury	1.34 (0.66–2.71)	1.82 (0.86–3.83)	0.72 (0.20–2.52)
Dermatological disease	0.86 (0.52–1.41)	0.86 (0.48–1.54)	1.51 (0.76–3.00)
Neurological disease	1.99 (1.20–3.30)	2.73 (1.56–4.76)	1.30 (0.57–2.98)
Endocrinological disease	0.65 (0.40–1.06)	0.67 (0.40–1.12)	2.80 (1.57–4.98)
Urological disease	1.55 (1.01–2.40)	0.78 (0.47–1.30)	2.39 (1.33–4.28)
Digestive disease	1.11 (0.74–1.67)	1.97 (1.30–3.01)	0.79 (0.42–1.47)
Musculoskeletal disease	0.91 (0.65–1.30)	1.50 (1.02–2.20)	1.86 (1.08–3.22)
Cardiovascular disease	1.48 (1.04–2.11)	4.01 (2.67–6.01)	1.66 (0.94–2.93)
Respiratory disease	0.98 (0.70–1.40)	1.19 (0.80–1.76)	0.94 (0.55–1.62)
Mental disorder	5.49 (3.61–8.40)	8.38 (5.33–13.18)	4.02 (2.30–7.02)

OR: odds ratio; CI: confidence interval.

In keeping with these findings, we support the conclusion of Smolders et al., that co-morbidity, especially psychiatric co-morbidity, in depressed patients leads to higher prescription levels of psychotropic medication.