What paper found 25% of patients are housebound/bedbound?

This is my analysis on PR from 2016 of the Pendergrast/Jason study and others, including looking at biases
https://forums.phoenixrising.me/thr...ebound-patients-with-me-cfs.44330/post-724544


Short version: The study provides support for a 25% rate of housebound/bedbound patients, based on a sample of over 500 patients from three different countries. The sample is likely to miss both the least severe and most severe cases, which increases the uncertainty.

An earlier study based on surveys of UK GP practices, likely to be more representative, didn't directly measure housebound status but supports a figure of at least 25%.
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Full version
There's a group in the UK specifically for the severely-affected (I used to be a member, when I was, and it was a huge help). It's called the 25% Group, the name taken for the proportion of patients either bedbound or housebound. I'd never been able to find peer-reviewed evidence for the 25% figure*, though it seems to be widely accepted and I have no good reason to challenge it. Peer-reviewed, published support for the figure would give it more weight eg in advocacy work - and 25% is a shocking figure.

[* this paper cites a 1990 book co-authored by Dr David Bell, and a 2001 Action for ME membership survey, that I can't access]

But this study new does provide some evidence for a 25% figure, which I thought might be a useful reference
mango said:
Results Findings indicated that the housebound group represented one quarter of the sample,
The actual figure in this study is 128/537=23.8%, ie a quarter.

The study said:
Housebound status. The DSQ includes a measure that asks participants to describe their fatigue/energy related illness.25 Participants that responded either ‘‘I am not able to work or do anything, and I am bedridden,’’ or ‘‘I can walk around the house, but I cannot do light housework,’’ were classified as Housebound. Participants that responded ‘‘I can do light housework, but I cannot work part-time,’’ or indicated more functioning (participating in family responsibilities, working part-time or fulltime) were classified as not housebound.
How representative is the sample of the wider patient population?

OK, so this isn't necessarily a representative sample - and as you can see below there are substantial differences between the samples on average age (35-52), proportion who were still working (10%-37.5%) and those with a post-grad qualification (10%-40%). There are no separate figures for the proportion who were housebound, but presumably differences would broadly reflect employment rates.

DePaul sample (USA), n=216 (39% of the total)
This sample was drawn from adults self-identifying as having CFS, ME, and ME/CFS. In order to accommodate participants unable to attend a clinic, a variety of Institution Review Boardapproved recruitment methods were implemented. These methods included posting on internet forums, visiting support groups, and contacting individuals who had expressed interest in past or future research studies at DePaul.

84% female, mean age 52, 40% had post grad education (so not very representative), 13.5% working part of full time.

Newcastle (UK) clinic sample, n=98
Diagnosed from referrals to a specialist clinic
83% female, mean age 46, 21% post-grad, 37.5% working part or full time

Norway 1, self-managment trial, n=174
Participants in a randomized trial of a CFS self-management program. Participants were recruited from various sources, including physicians, waiting lists for patient education programs, and CFS patient organizations in the communities surrounding Oslo. Participants were required to be at least 18 years old with a diagnosis of CFS by a physician

87% female, mean age 43, 10% post-grad, 10% working part or full time

Norway 2, inpatient and outpatient clinic, n=63
The second Norway sample was composed of inpatients medical and outpatients at a multidisciplinary ME/CFS Center. Clincial diagnosis. Eligible participants were between 18 and 65 years of age

83% female, mean age 35, 11% post-grad, 19% working part or full time

It's likely that clincs miss out on less severe cases, which might never get referred. Self-selected samples like the DePaul convenience one, are similarly likely to underrepresent less severe cases. That could lead to a misleadingly high proportion of severe cases in these samples. On the other hand, many/most bedboud patients won't be able to attend clinics so are effectively excluded from the specialist system as home-visits are virtually non-existent (in the UK at least). So that will lead to undercounting.

As there could be biases both ways (over and undercounting the proportion who are housebound), that adds more uncertainty around the figure, but is no reason to reject it ie this is some evidence, from an international sample of 500+ patients, that supports a 25% figure for the housebound/bedbound.

UK GP study looking at functional impairment (Nacul 2011)
An earlier study in the UK is based on GP practices so is more likely to be representative of the wider patient population. (Though practices were chosen for having GPS who had experience of diagnosing mecfs so weren't entirely representative of the UK population, and diagnosis wasn't independently confirmed by specialist physicians.)
The functional status and well being of people with myalgic encephalomyelitis/chronic fatigue syndrome and their carers | BMC Public Health | Full Text

While this doesn't measure housebound status, it gives SF36 survey scores, which gives clues.
25% of patients scored 10 or less on the Physical Function subdomain. You get ten points for being able to wash and dress, but not, eg climb a flight of steps or walk a block - even with difficulty. So you would expect all of them to be housebound, especially as some will score less than ten (struggle/can't do personal care). In fact, it may well be more 25%, but you can't tell from the data provided (interquartile range).

The poor level of functioning is supported by (at least) 25% scoring 0 for 'Role Physical', which means physical health problems interfere with everything you do, and 25% (or more) scoring 12.5 (or lower) for Social Functioning, which equates to your health interfering quite a bit/extremely with social activity with friends and family.

(SF-36® Health Survey Scoring Demonstration)

I'll stop there, this is already too long and geeky by far.