Evidence map›Paper›PMID 28877680›Full record

SynthesisBMC medical research methodology2017

Longitudinal studies that use data collected as part of usual care risk reporting biased results: a systematic review.

Delaram Farzanfar, Asmaa Abumuamar, Jayoon Kim, Emily Sirotich, Yue Wang, Eleanor Pullenayegum

Abstract readSystematic Review
In one paragraph

Synthesis in BMC medical research methodology, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 9 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
9citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

9 citing papers in PubMed, 1 synthesis or guideline pooled it.

  1. Pooled it
  2. Article
  3. Article
  4. Review
  5. Article
  6. Article
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Delaram FarzanfarUniversity Health Network, University of Toronto, Toronto, M5T 2S8, Canada. delaram.farzanfar@mail.utoronto.ca.ORCID http://orcid.org/0000-0003-2112-2181
Asmaa AbumuamarInstitute of Medical Science, University of Toronto, City, ON, M5S 1A8, Canada.
Jayoon KimFaculty of Arts & Science, University of Toronto, City, ON, M5S 3G3, Canada.
Emily SirotichFaculty of Arts & Science, University of Toronto, City, ON, M5S 3G3, Canada.
Yue WangFaculty of Arts & Science, University of Toronto, City, ON, M5S 3G3, Canada.
Eleanor PullenayegumChild Health Evaluative Sciences, The Hospital for Sick Children, Toronto, ON, M5G 1X8, Canada.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundLongitudinal studies using data collected as part of usual care risk providing biased results if visit times are related to the outcome of interest. Statistical methods for mitigating this bias are available but rarely used. This lack of use could be attributed to a lack of need or to a lack of awareness of the issue.

methodsWe performed a systematic review of longitudinal studies that used data collected as part of patients' usual care and were published in MEDLINE or EMBASE databases between January 2005 through May 13

resultsOf 44 eligible articles, 57% (n = 25) reported on the total follow-up time, 7% (n = 3) on the gaps between visits, and 57% (n = 25) on the number of visits per patient; 78% (n = 34) reported on at least one of these. Two studies assessed predictors of visit times, and 86% of studies did not report enough information to assess whether there was a need to account for informative follow-up. Only one study used a method designed to account for informative visit times.

conclusionsThe low proportion of studies reporting on whether there were important predictors of visit times suggests that researchers are unaware of the potential for bias when data is collected as part of usual care and visit times are irregular. Guidance on the potential for bias and on the reporting of longitudinal studies subject to irregular follow-up is needed.

Indexed as

Data CollectionLongitudinal StudiesBiasHumansPatient ParticipationRisk FactorsTimeAdministrative dataBiasLongitudinal dataStatistical methods

Identifiers

PMID28877680
PMCPMC5588621

What OpenQuestion holds

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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.