Collin, Crawley, White: Trends in the incidence of CFS and FM in the UK

[Dolphin]

Initial onset is often relapse-remission for teenagers, later to develop into continuous illness for many, and this is something that is not effectively captured with the methodology of this study. The data is what it is, just important not to jump to conclusions about duration with such limitations.

Just to point out to anyone who hasn't read it, the current study gives no information on duration.

 

[Jonathan Edwards]

I know that. I don't see how that explains these figures:

Agreed, nor do I. If the length of illness was lifelong then their figures might add up but since they are only studying <20 yr olds that won't work anyway. If illness lasts 12 months, as in their first option, then incidence should equal prevalence as far as I can work out.

 

[Dolphin]

If people were given two different diagnostic labels would they be counted once or twice?

If it is only once, this could underestimate how many people have been diagnosed with a particular condition. For example somebody could have fibromyalgia and also CFS/ME.

I wasn't paying close attention when I read it on this issue.

These extracts make me think somebody would only be counted once.

Diagnoses.

Patients were identified by Read code (Supplementary Table 1) as having an event – chronic fatigue syndrome (CFS/ME), fibromyalgia (FM), post-viral fatigue syndrome (PVFS), or asthenia/ debility diagnosis or referral to a CFS/ME specialist service – during the study period (1 January 2001 to 31 December 2013). The ‘index event’ was the earliest event of interest for a patient during the study period and within the practice’s up-to-standard (UTS) period and the patient’s UTS registration period. Patients were required to have at least 12 months of UTS data prior to the index event. For the purpose of estimating incidence rates, we considered incident, i.e. ‘new’, diagnoses to be those index events for which there were no preceding diagnosis of CFS/ME, FM, PVFS, or asthenia/debility in the patient’s Clinical Practice Research Datalink (CPRD) medical record. Read codes for referral to specialist services were introduced in 2010. Diagnoses which were made after a referral and which occurred within the patient’s UTS period (and for which there was no prior diagnosis) were treated as incident diagnoses.

Population-wide incidence of CFS/ME in Norway from 2008 to 2012 as indicated by ICD-10 code G93.3 (‘post-viral fatigue syndrome/benign myalgic encephalomyelitis’) was 25.8 (25.2, 26.5) per 100,000 person years.33 This is 74% higher than the incidence in our study, possibly because the ICD-10 code combines PVFS and CFS/ME in a single classification.

 

[RogerBlack]

I note https://www.ncbi.nlm.nih.gov/pubmed/15574853
Incidence of fatigue symptoms and diagnoses presenting in UK primary care from 1990 to 2001.

I have not studied this paper in depth. White is also an author on this one.

 

[Keith Geraghty]

If the assumed average duration of illness for under 20s is 12-24 months - is this not an indirect way of saying the majority of under-20s recovery within 1-2 years? I suspect without intervention --- meaning only long-term sufferers require CBT/GET - as whats the point in throwing CBT/GET at 100% cohort with CBT lasting an average 6-12 months, when the average sufferer will be better by that stage


I cant quite work out the calculation of under 20s incidence -- I know they had roughly 6710 adults and 916 children in their data. I have a rough calculation of 14 million kids under 18, (15 million under 20 in the UK pop) - I think using their own figures this would be a ratio of kids to adults 15% kids -- so one could start guessing around if adults have say 250,000 to 500,000 --- can we start working out under 18s to be roughly 35,000 to 70,000 and then can we go back to this data and work out some point or period prevalence ?

Now bare in mind that the data comes from a cross section of say 660 GP clinics - it wont include any patients who drop out or move around - unless captured in one year. I have been running some calcuations all day and I cant seem to get the maths to add up

am I missing something - have a go and see what you come up with - our maths game of the day?