MC1R Mutations Associated With Red Hair and Perioperative Anesthesia Complications (MARPAC)

September 10, 2026 updated by: Uppsala University

The Presence of Red Hair Associated MC1R Mutations and the Incidence of Perioperative Anesthesia Complications: A Cohort Study

The study aims to investigate whether patients with Melanocortin-1 receptor (MC1R) mutations, associated with red hair, or having a red hair phenotype, have a higher incidence of anesthesia-related perioperative complications. Genomic data from patients that have undergone a surgical or medical procedure, requiring an anesthetic management are extracted from two cohorts - a Swedish (Merged Anaesthesia and Intensive Care Cohort in Sweden (MAICS)), and a British (UK Biobank UKBB)), and linked to relevant healthcare registries. The outcome variables studied are statistically adjusted for age, gender, timing of procedure during the study period, and socioeconomic factors.

Study Overview

Detailed Description

Background Perioperative complications may be associated with both suffering for the affected individuals, and a high cost for society. Available means for identifying individuals at risk should be considered.

Objective To investigate whether patients with MC1R variants (Asp84Glu, Arg142His Arg151Cys, Tyr152Ochre, Ile155Thr, Arg160Trp, Arg213Trp, Asp294His, or Arg306His) associated with red hair, or having a red hair phenotype have an increased incidence of anesthesia related perioperative complications.

Method This is a retrospective registry-based study including patients from one Swedish cohort (MAICS), and one British cohort (UKBB). MAICS is aggregation of four different cohorts; PronMed, Epihealth, Simpler, and the Swedish Twin Registry (STR). The Patients are selected from the Swedish National Patient Registry (NPR), and the Hospital Episode Statistics (HES)/NHS England using surgical and medical procedure codes known for requiring an anesthetic management in the form of general anesthesia, spinal/epidural anesthesia or regional anesthesia.

Eligible patients are associated with genotype data, and stratified into either homozygote/compound heterozygote, heterozygote, or wildtype to be able to assess whether a dose-response relationship exists between the different levels of exposures. From UKBB, a separate analysis of the association between red hair phenotype and perioperative complications is performed.

Outcome ascertainment, and the defining of cases and non-cases, is perfomed using healthcare linkage to Swedish Perioperative Registry (SPOR), Swedish Intensive Care Register (SIR), National cause of death registry (DORS), Statistics Sweden, and UKBB.

The results will be analyzed using a statistical mixed effects model, adjusted for age, sex, timing of surgery during the study period, and socioeconomic factors. The results of the genotype analysis from the two cohorts will be meta-analyzed.

Study Type

Observational

Enrollment (Estimated)

100000

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

      • Uppsala, Sweden, 75185
        • Uppsala University, Department of Surgical Sciences
        • Contact:
        • Principal Investigator:
          • Miklós Lipcsey, MD, PhD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The population consists of all available patients registered in either NPR/Sweden or HES/UKBB with a qualifying procedure code, and having been genotyped for a defined MC1R variant.

Description

Inclusion Criteria:

  • A qualifying surgical procedure requiring specified anesthetic management.
  • A qualifying medical procedure requiring specified anesthetic management.
  • Caucasian origin.

Exclusion Criteria:

  • None specified.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Exposure (high
Individuals from either MAICS or UKBB being homozygote/compound heterozygote for MC1R mutations, OR individuals from UKBB consistently reporting red hair phenotype.
Exposure (intermediate)
Individuals from either MAICS or UKBB being heterozygote for MC1R mutations, OR individuals from UKBB with diverse reporting of having red hair phenotype.
Non-exposure (control)
Individuals from either the MAICS or the UKBB databases carrying a MC1R wildtype, OR individuals from UKBB reporting a hair color other than red.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serious adverse events occurring after a surgical, or medical procedure requiring anesthetic.
Time Frame: Days 30 after a qualifying procedure.
A composite of adverse events consisting of Death, Unplanned ICU-admission, Myocardial arrest (ICD10: I46), Myocardial infarction (ICD10: I21-22), Pneumonia (ICD10: J13-16, J18, J85, J86, A481), and Anaphylaxis (ICD10: T782, T805, T886) Up until 30 days after the procedure.
Days 30 after a qualifying procedure.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Serious adverse events occurring after a surgical, or medical procedure requiring anesthetic.
Time Frame: Days 30 after a qualifying procedure.
The variables in the composite outcome analyzed one by one.
Days 30 after a qualifying procedure.
Adverse events registered at the post anesthesia care unit (PACU)
Time Frame: Hours 24 after a qualifying procedure.
Tachy-/bradycardia, arrythmia, angina, heart failure, hypo-/hypertension, and unexpected bleeding registered in the Swedish Perioperative Register (SPOR) from patients originating from the Swedish cohort.
Hours 24 after a qualifying procedure.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

December 1, 2026

Study Registration Dates

First Submitted

September 4, 2026

First Submitted That Met QC Criteria

September 10, 2026

First Posted (Actual)

September 11, 2026

Study Record Updates

Last Update Posted (Actual)

September 11, 2026

Last Update Submitted That Met QC Criteria

September 10, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The data that support the findings of this study are available from the respective national registries in Sweden with restrictions as defined by the General Data Protection Regulation (GDPR), the Swedish Personal Data Act (1998:204), and the licenses with the respective national registries, and so are not publicly available. Data are however available from the respective national registries after reasonable request and adequate permissions from the Swedish ethical review authority under the restrictions outlined above.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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