Associations of physical and psychiatric conditions with CFS in Germany: an exploratory case-control study. Jacob et al. 2020

[John Mac]

Full title: Associations of physical and psychiatric conditions with chronic fatigue syndrome in Germany: an exploratory case-control study

Background
Only a few studies have analyzed the effects of physical and psychiatric conditions on the risk of chronic fatigue syndrome (CFS). Therefore, the goal of this exploratory case-control study was to investigate the associations of physical and psychiatric conditions with CFS in almost 19 800 adults from Germany.

Methods
This study included patients diagnosed for the first time with CFS in one of 1238 general practices in Germany between 2010 and 2017 (index date). Controls without CFS were matched (1:1) to cases with CFS by sex, age, index year, and practice. Physical and psychiatric conditions diagnosed in the year prior to the index date were included if they were present in at least 3% of patients with CFS. Associations between physical and psychiatric conditions (33 potential independent variables) and CFS (dependent variable) were analyzed in an adjusted conditional logistic regression model, and physical and psychiatric disorders were included in the model using forward stepwise selection.

Results
This study included 9896 cases with CFS and 9896 controls without CFS [65.1% women; mean (standard deviation) age 49.5 (18.3) years]. Seven conditions were associated with CFS in the adjusted regression model. The disorders displaying the strongest relationship with CFS were cancer [odds ratio (OR) = 2.57, 95% confidence interval (CI) = 2.24–2.95], sleep disorders (OR = 1.88, 95% CI = 1.66–2.12) and depression (OR = 1.77, 95% CI = 1.61–1.95).

Conclusions
Cancer, sleep disorders, and depression were strongly and positively associated with CFS. Additional studies are needed to gain a better understanding of the mechanisms underlying these relationships.

https://www.cambridge.org/core/jour...ontrol-study/3EF0A2F5558707BB90526F10FE83C1CF

 

[Trish]

I wonder how many of these are misdiagnoses of CFS. It seems to be pretty well known that some cancer treatments cause fatigue symptoms, and depression also includes fatigue as a symptom, and sleep disorders are likely to leave the sufferer fatigued or at least tired all the time. So it may be not so much that cancer, depression or sleep disorders cause CFS, as the fatigue associated with these conditions and/or their treatments, is being misdiagnosed as CFS.

 

[Dolphin]

An important issue with so-called prospective studies for ME/CFS is that in the period allegedly before patients had ME/CFS, they could have had it but just not been diagnosed.

This paper may perhaps mention this possibility but I’ve seen some that haven’t.

 

[Hoopoe]

Germany doesn't really recognize CFS and I think most patients would be diagnosed with depression or somatization disorder.

 

[Hutan]

This study included 9896 cases with CFS and 9896 controls without CFS [65.1% women; mean (standard deviation)

It's always interesting to see the male:female ratio in ME/CFS studies from different cultures. 65% female in diagnosed CFS cases is towards the lower end of the range of what we often see.

 

[Snow Leopard]

Depression was found in 15.6% of CFS patients, which does not seem like an unreasonable estimate.
Cancer prevalence was 6.4% in CFS patients, which seems high, given a rate of 1.9% in age matched controls. In principle, there shouldn't be a presentation bias for cancer in CFS patients, unless the cancer is a risk factor for CFS or vice versa (a very large NIH study found that CFS only has one cancer association: lymphoma).

A reasonably long of other physical conditions were also associated with CFS.

Germany doesn't really recognize CFS and I think most patients would be diagnosed with depression or somatization disorder.

Yes, retrospective analyses of medical records suffer from biases of diagnosis, which is to say biased by the behaviour of doctors.