Published Research
Peer-reviewed medical research
Dr Christoph Schnelle is the first author on ten published peer-reviewed medical research journal articles and five patents. The main subject of the articles is medical doctors and their performance, same as his 2023 PhD, an area he is an expert in.
Christoph’s Google Scholar profile links to all of these documents and shows the number of citations for each.
Six of the articles were Dove Publishing publications, all in 2022.
The latest article was published in an Elsevier journal, Heliyon Publishing.
Below are links and abstracts for these articles listed by year of publication.
2023
Characteristics of exceptionally good Doctors — A survey of public adults
Link to full article
Highlights
• 86% of members of the public remember at least one exceptionally good doctor.
• Such doctors are outstanding communicators, or diagnosticians, or interventionists.
• Exceptionally good doctors who willingly listen to patients to the end:
• Such doctors stand out even among exceptionally good doctors.
• They are considered more knowledgeable, caring, honest, with more integrity.
Abstract
Background
Systematic reviews have found that doctors can have a substantial effect on patients’ physical health, beyond what can be explained by known factors. In a previous qualitative study, 13 medical doctors were interviewed on their experiences of exceptionally good doctors, and all had met at least one such doctor.
Objective
To determine how common it is for exceptionally good doctors to be encountered by patients and what are the characteristics of exceptionally good doctors.
Design
Mixed methods cross-sectional survey of 580 Amazon Mechanical Turk participants. Questions included doctor and participant demographics, and 34 Likert questions on characteristics of exceptionally good and average doctors. Free-text questions allowed participants to describe exceptional doctors, record their experience, and provide survey feedback. Stratified sampling ensured gender parity and 33% of participants aged ≥55 years. Analysis included descriptive statistics, statistical modelling of associations between Likert scale scores and patient demographics, and factor analysis.
Results
Of 580 responses, 505 (86%) were included in the analysis. Factor analysis confirmed internal validity. Most respondents (86%) had met at least two exceptionally good doctors, of whom 55% were specialists. 58% of respondents regarded doctors as exceptional based on an overall impression with multiple reasons. Doctors were most commonly considered exceptional based on one or more of their personality, diagnostic, or intervention ability. Respondents who reported the doctors “willingly listened to them to the end” scored their doctors higher on 33 of 34 Likert questions, except for popularity. They also rated average doctors lower throughout.
Conclusions
Exceptionally good doctors appear to be commonly encountered by the adult public. Listening to patients willingly to the end is a highly rated and influential characteristic, suggesting that listening could be targeted for quality improvement.
Keywords
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Medical practice
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Good doctors
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Doctors' performance
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Patients' opinion
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Survey
2022
Is There a Doctors’ Effect on Patients’ Physical Health, Beyond the Intervention and All Known Factors? A Systematic Review
Abstract
Purpose:
Despite billions of doctor visits worldwide each year, little is known on whether doctors themselves affect patients’ physical health after accounting for intervention and confounders such as patients’ and doctors’ data, hospital effects, nor how strong that doctors’ effect is. Knowledge of surgeons’ and psychotherapists’ effects exists, but not for 102 other medical specialties notwithstanding the importance of such knowledge.
Methods: Eligibility Criteria: Randomized controlled trials (RCTs), case-control, and cohort studies including medical doctors except surgeons for any intervention, reporting the proportion of variance in patients’ outcomes owing to the doctors (random effects), or the fixed effects of grading doctors by outcomes, after multivariate adjustment. Exclusions: studies of < 15 doctors or solely reporting doctors’ effects for known variables.
Sources:
Medline, Embase, PsycINFO, inception to June 2020. Manual search for papers referring/referred to by resulting studies.
Risk of Bias:
Using Newcastle–Ottawa scale.
Results:
Despite all medical interventions bar surgery being eligible, only thirty cohort papers were found, covering 36,239 doctors, with 10 specialties, 21 interventions, 60 outcomes (17 unique). Studies reported doctors’ effects by grading doctors from best to worst, or by diversely calculating the doctor-attributed percentage of patients’ outcome variation, ie the intra-class correlation coefficient (ICC). Sixteen studies presented fixed effects, 18 random effects, and 3 another approach. No RCTs found. Thirteen studies reported exceptionally good and/or poor performers with confidence intervals wholly outside the average performance. ICC range 0 to 33%, mean 3.9%. Highly diverse reporting, meta-analysis therefore not applicable.
Conclusion:
Doctors, on their own, can affect patients’ physical health for many interventions and outcomes. Effects range from negligible to substantial, even after accounting for all known variables. Many published cohorts may reveal valuable information by reanalyzing their data for doctors’ effects. Positive and negative doctor outliers appear regularly. Therefore, it can matter which doctor is chosen.
Keywords: physicians’ effect, practice effect, physicians’ practice pattern, clinical competence, professional practice gap, delivery of health care, quality of health care, physicians.
Is There a Surgeons’ Effect on Patients’ Physical Health, Beyond the Intervention, That Requires Further Investigation? A Systematic Review
Abstract
Objective:
To find and review published papers researching surgeons’ effects on patients’ physical health. Clinical outcomes of surgery patients with similar prognoses cannot be fully explained by surgeon skill or experience. Just as there are “hospital” and “psychotherapist” effects, there may be “surgeons” effects that persist after controlling for known variables like patient health and operation riskiness.
Methods:
Cohort studies and randomized controlled trials (RCTs) of any surgical intervention, which, after multivariate adjustment, either showed proportion of variance in patients’ physical health outcomes due to surgeons (random effects) or graded surgeons from best to worst (fixed effects). Studies with < 15 surgeons or only ascribing surgeons’ effects to known variables excluded. Medline, PubMed, Embase, and PsycINFO were used for search until June 2020. Manual search for papers referring/referred by resulting studies. Risk of bias assessed by Cochrane risk-of-bias tool and Newcastle–Ottawa Scale.
Results:
Included studies: 52 cohort studies and three RCTs of 52,436+ surgeons covering 102 outcomes (33 unique). Studies either graded surgeons from best to worst or calculated the intra-class correlation coefficient (ICC), the percentage of patients’ variation due to surgeons, in diverse ways. Sixteen studies showed exceptionally good and/or bad performers with confidence intervals wholly above or below the average performance. ICCs ranged from 0 to 47%, median 4.0%. There are no well-established reporting standards; highly heterogeneous reporting, therefore no meta-analysis.
Discussion: Interpretation:
There is a surgeons’ effect on patients’ physical health for many types of surgeries and outcomes, ranging from small to substantial. Surgeons with exceptional patient outcomes appear regularly even after accounting for all known confounding variables. Many existing cohort studies and RCTs could be reanalyzed for surgeons’ effects especially after methodological reporting guidelines are published.
Conclusion:
In terms of patient outcomes, it can matter which surgeon is chosen. Surgeons with exceptional patient outcomes are worth studying further.
Keywords:
physicians, physicians’ effect, doctors’ effect, therapists’ effect, practice effect, clinical competence, professional practice gap, surgeons’ practice pattern, quality of health care, delivery of health care.
The Doctors’ Effect on Patients’ Physical Health Outcomes Beyond the Intervention: A Methodological Review
Abstract
Background:
Previous research suggests that when a treatment is delivered, patients’ outcomes may vary systematically by medical practitioner.
Objective:
To conduct a methodological review of studies reporting on the effect of doctors on patients’ physical health outcomes and to provide recommendations on how this effect could be measured and reported in a consistent and appropriate way.
Methods:
The data source was 79 included studies and randomized controlled trials from a systematic review of doctors’ effects on patients’ physical health. We qualitatively assessed the studies and summarized how the doctors’ effect was measured and reported.
Results:
The doctors’ effects on patients’ physical health outcomes were reported as fixed effects, identifying high and low outliers, or random effects, which estimate the variation in patient health outcomes due to the doctor after accounting for all available variables via the intra-class correlation coefficient. Multivariable multilevel regression is commonly used to adjust for patient risk, doctor experience and other demographics, and also to account for the clustering effect of hospitals in estimating both fixed and random effects.
Conclusion:
This methodological review identified inconsistencies in how the doctor’s effect on patients’ physical health outcomes is measured and reported. For grading doctors from worst to best performances and estimating random effects, specific recommendations are given along with the specific data points to report.
Protocol for a Qualitative Study on Doctors’ Opinions on and Experiences of Exceptionally Good Doctors
Characteristics of exceptionally good doctors: A protocol for a cross-sectional survey of adults
Abstract
Objective:
Doctors have a varying effect on patients’ physical health. This means that there are doctors that are more effective than others. Even though the doctor is a part of very many medical interactions, it is not known in which way exceptionally good doctors differ from their peers. After authoring two systematic and one methodological review on identifying exceptional doctors, the authors in this qualitative interview-based study take a bottom-up, inductive approach to answer the question of what makes an exceptionally good doctor.
Methods:
About 10– 15 semi-structured interviews of medical doctors of any specialty who speak English will be conducted. Recruitment will be through the authors’ network and their referrals. Questions will be whether they have an opinion on what makes an exceptionally good doctor, whether they have met such a person and how did this doctor differ from other doctors. The interviews will be done by a 62-year old PhD student who is not a clinician but has extensive experience in having personal conversations as a financial adviser. This could be helpful as the interviewer is only aware that there are exceptionally good doctors but has no notion how exceptionally good doctors differ from their colleagues.
Analysis:
A six-phase thematic analysis in an experiential framework as per Braun and Clarke will be implemented with the aim to find out what the doctors think and have experienced. This is an inductive approach using a realist epistemological position under the assumption that it is possible to acquire truthful knowledge on what makes exceptionally good doctors.
Discussion:
Previous qualitative research on exceptionally good doctors consisted of interviewing author-selected exceptionally good doctors. This study takes a step back from this approach by asking the peers of exceptionally good doctors how they define being exceptionally good and how they experience such doctors.
Keywords: qualitative study, thematic analysis, doctors’ performance.