The challenge of opt-outs from NHS… | 2018

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43/100

✓ Peer-reviewed alzhub usefulness score 43 out of 100. Risk factors

Topic: Risk, prevention and care in population studies

As a result, NHS data provide a huge and invaluable resource of routinely collected primary (e.g. visits to GP practices) and secondary (e.g. hospital admissions, outpatient appointments, A&E attendances) healthcare data covering near-100% of the population of England. Although the exact overall number of patients who opted out, either through type 1 or 2 (or both), cannot be calculated from data released by NHS Digital, we would expect some double-counting between the two types of opt-outs, resulting in a lower national prevalence than the 5.46% given above. OP data suggest that opt-out rates are significantly higher (P 10%, including 24 with a prevalence >50%. The quality of data on opt-outs depends on GP practices reporting both the number of opt-outs (numerator) and the overall number of patients registered at GP practices (denominator). Overall, the vast majority of GP practices report both counts. There were 58,880,877 patients registered at GP practices on 1 December 2017.12 This is higher than the overall estimated population of England in mid-2017 (55 765 513)13 suggesting that a substantial number of patients might be registered in more than one GP practice or have died but not been removed from registers—often termed ‘ghost patients’.14 We have carried out analysis of opt-out data from consecutive time periods and identified a range of inconsistencies which could partly explain the differences in numbers of patients registered, including (i) GP practices reporting relatively implausible decreases (up to 65%) in either the number of patients registered or patients opting out; and (ii) double-counting of patients for several months after the merging of several local GP practices. We linked data on opt-outs for December 2017 released by NHS Digital with postcodes from GP practices, also available from NHS Digital (https://digital.nhs.uk/organisation-data-service/data-downloads/gp-data) and geographical coordinates associated with postcode centroids, available from the Ordnance Survey Open Data (https://www.ordnancesurvey.co.uk/business-and-government/products/code-point-open.html). For example, the prevalence of type 2 opt-outs in Camden in North London was 9.06%, compared with 1.04% in Kensington and Chelsea in Central London and 2.3% on average in England. Lower Super Output Areas (LSOA, available from the Open Data Communities (https://www.gov.uk/government/statistics/english-indices-of-deprivation-2015)) suggested a statistically significant as

Key findings

As a result, NHS data provide a huge and invaluable resource of routinely collected primary (e.g. visits to GP practices) and secondary (e.g. hospital admissions, outpatient appointments, A&E attendances) healthcare data covering near-100% of the population of England.
Although the exact overall number of patients who opted out, either through type 1 or 2 (or both), cannot be calculated from data released by NHS Digital, we would expect some double-counting between the two types of opt-outs, resulting in a lower national prevalence than the 5.46% given above.
OP data suggest that opt-out rates are significantly higher (P 10%, including 24 with a prevalence >50%.
The quality of data on opt-outs depends on GP practices reporting both the number of opt-outs (numerator) and the overall number of patients registered at GP practices (denominator).
Overall, the vast majority of GP practices report both counts.

Why it matters

This paper discusses challenges with patients opting out of NHS data sharing and how this affects small-area health data. It has no findings about treating, curing, or preventing Alzheimer's disease.

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Study details

Effect size3.07%; 2.39%; 5.46%
Evidence strengthModerate

How this study scored 43/100

Published in a peer-reviewed journal. Scored zero for study design, sample size, studied in people and randomised / blinded because the record does not state it.

Component	Points	Why
Journal tier	7 / 10	Tier 3 — peer-reviewed journal (Journal of Public Health)
Journal's citation record	1 / 4	Journal of Public Health: journal h-index 137 (OpenAlex, 2026-10-29)
Study design	0 / 12	No study design recorded — scores zero, not guessed (not stated in the record — scored 0)
Strength of evidence	3 / 5	Rated “moderate” in our summary
Peer-review validation	10 / 10	Peer-reviewed. Published as an article in a named peer-reviewed journal.
How recent	2 / 5	2018 — within 10 year(s) of the newest study here
Sample size	0 / 4	Participant count not stated — scores zero (not stated in the record — scored 0)
Effect reported	2 / 3	Effect reported as a number, without an interval or test
Studied in people	0 / 3	Not stated whether this was studied in people — scores zero (not stated in the record — scored 0)
Randomised / blinded	0 / 2	No randomisation or blinding stated — scores zero (not stated in the record — scored 0)
Times cited	3 / 7	Cited 24 times (OpenAlex, 2026-10-10)
Citations per year	1 / 5	2.4 citations a year over 10 year(s) since 2018
Impact for its field and year	2 / 6	Cited 2.4× the average for papers of its field and year (OpenAlex FWCI)
Cited by studies here	0 / 6	No other study in this library cites it
Still being cited	1 / 4	Cited 12 times in 2024–2026 (2026 still in progress; OpenAlex)
Senior author's track record	4 / 4	Last-listed author Paul Elliott: h-index 166 (OpenAlex, whole career)
Institution's track record	2 / 3	Imperial College London: institution h-index 1,744 (OpenAlex)
Multi-centre collaboration	1 / 3	OpenAlex lists 2 institution(s) in 1 country
Indexed in PubMed	2 / 2	Indexed in PubMed (PMID 29590471)
Free to read	2 / 2	Free to read
Total	43 / 100	—

What each of these 20 components measures, and what this score is not →

Read the original

Full text: free to read — OpenAlex lists this copy as free to read: the link above (checked 6 Feb 1020).

Cite this study APA, Vancouver, BibTeX · download .bib or .ris

Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.

APA 7th

Piel, F. B., Parkes, B. L., Daby, H. I., Hansell, A., & Elliott, P. (2018). The challenge of opt-outs from NHS data: a small-area perspective. Journal of Public Health. https://doi.org/10.1093/pubmed/fdy059

Vancouver

Piel FB, Parkes BL, Daby HI, Hansell A, Elliott P. The challenge of opt-outs from NHS data: a small-area perspective. Journal of Public Health. 2018. doi:10.1093/pubmed/fdy059. PMID: 29590471.

BibTeX

@article{piel2018-29590471,
  author  = {Piel, Frédéric B. and Parkes, Brandon L. and Daby, Hima Iyathooray and Hansell, Anna and Elliott, Paul},
  title   = {{The challenge of opt-outs from NHS data: a small-area perspective}},
  journal = {Journal of Public Health},
  year    = {2018},
  doi     = {10.1093/pubmed/fdy059},
  pmid    = {29590471},
  url     = {https://doi.org/10.1093/pubmed/fdy059}
}

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