Chronic Pain in the General Population of Chile (RDC)

Chronic Pain in the General Population of Chile: Longitudinal Study

The present study seeks to follow up the cohort of adults representative of Chile's urban population whose levels of chronic pain were evaluated in March 2023 (baseline) as part of the Mental Health Thermometer (MHT) study. The study consists of a 12 month follow-up telephone interview to assess parameters of chronic pain (CP) and subtypes, mental and physical health, lifestyle and adversity and work characteristics.

The study objectives are as follows:

1. Estimate the prevalence of CP and subtypes in the general population
2. Explore the association between mental health indicators, perceived work stress and presence of CP in the population.
3. Investigate the impact of CP (functional, occupational and social) among the subset of participants reporting CP
4. Describe the use of management strategies in those who suffer from CP.

Study Overview

• Status: Completed
• Conditions: Chronic Pain; Insomnia; Fibromyalgia; Neuropathic Pain; Loneliness; Depression, Anxiety; Self Harm; Migraine Disability

Detailed Description

I. Aims of the study:

1. Estimate the prevalence of chronic pain (CP) and subtypes in the
2. Explore the association between mental health indicators, perceived work stress and the presence of CP in the urban population of Chile.
3. Asses the functional, occupational and social impact of CP in Chile´s urban population reporting CP.
4. Describe the use of management strategies in those who suffer from CP.

II. Design:

The design is longitudinal prospective and involves following up the same group of participants from the MHT study to monitor their mental health and CP parameters.

III. Study variables include:

3.1. Main outcome measures (instrument): Presence of chronic pain in the last 3 months, Severity of chronic pain (Chronic pain grade questionnaire; CPG), chronic pain interference in daily activities, social activities and work (CPG), depression (Patient Health Questionnaire; PHQ-9), anxiety (General Anxiety Disorder (GAD-7) 3.2. Secondary outcome measures: chronic pain management strategies, migraine disability (Migraine Disability Assessment, MIDAS), neuropathic pain (Neuropathic pain DN4 Questionnaire; DN4), fibromyalgia (Fibromyalgia Survey Questionnaire; FSQ), insomnia (Insomnia Severity Index; ISI), loneliness (3-item UCLA Loneliness Scale; R-UCLA) 3.3. Variables of interest: job-relates stress (Copenhagen Burnout Inventory; CBI), childhood adversity (Adverse childhood experiences; ACE), negative life events.

IV. Groups:

For the longitudinal analysis, participants will be classified into four groups:

• Group 1 (no pain): participants who do not declare CP at baseline or follow-up
• Group 2 (incident): participants who do not declare CP at baseline but declare it at follow-up.
• Group 3 (remitted): participants who declare CP at baseline but do not declare it at follow-up.
• Group 4 (chronic pain at follow-up): participants who declare CP at baseline and follow-up

V. Analysis plan:

5.1. Cross-sectional analysis (at follow-up)

• Prevalence of CP will be calculated (with 95% confidence interval (CI)) for the Chilean urban population by sex, age group and employment status (aim 1).
• Prevalences of the most common CP syndromes (i.e. migraine, fibromyalgia, neuropathic pain) with 96% CI will also be calculated.
• In the subset of the population with CP, descriptive analyzes will be carried out (percentages, means and standard deviation) of the interference levels (aim 3) and chronic pain management strategies (aim 4) by sex, age group and employment status.
• Calculation of Odds Ratios (ORs) with 95% CI for the main mental health variables associated with the presence of CI (i.e. symptoms of depression and anxiety) and for work variables (i.e. work-related stress), using logistic regression, adjusting for age, sex, physical health characteristics (aim 2).

5.2. Longitudinal analysis (baseline and follow-up)

• The database will be integrated with the baseline data and based on the distribution of certain sociodemographic and health variables in the two times, an attrition analysis will be carried out to conclude on the selective loss of subjects.
• Four groups will be created according to the pain trajectory between the two measurement points (see group section) and the proportion of new cases in the 12 months will be calculated (i.e. annual incidence).
• The difference in the chronic pain intensity reported at the measurement points will be calculated.
• Several multilevel models will be analyzed to examine the relationship between mental health (PHQ-9 and GAD- 7), sleep difficulties (ISI), perception of loneliness (UCLA-R), health variables (alcohol consumption, tobacco, body mass) and work variables (i.e. job satisfaction, work-related stress) and changes in the magnitude of perceived CP at 12 months, using linear and non-linear mixed effects models (aim 3).

• Study Type: Observational
• Enrollment (Actual): 2365

Contacts and Locations

Study Locations

• Chile
  • RM
    • Santiago, RM, Chile, 7550139
      • Pontificia Universidad Catolica de Chile

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Community survey in Chile

Description

Inclusion Criteria:

• General population
• Residence in urban areas

Study Plan

How is the study designed?

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort
Longitudinal analysis group 1 (no pain); Participants (general population residing in urban areas of Chile aged 18 years or more) not reporting chronic pain in march 2023 or march 2024
Longitudinal analysis group 2 (incident chronic pain); Participants (general population residing in urban areas of Chile aged 18 years or more) not reporting chronic pain in march 2023 but reporting chronic pain in march 2024
Longitudinal analysis group 3 (remitted chronic pain); Participants (general population residing in urban areas of Chile aged 18 years or more) reporting chronic pain in march 2023 but not reporting it in march 2024
Longitudinal analysis group 4 (chronic pain at follow up); Participants (general population residing in urban areas of Chile aged 18 years or more) reporting chronic pain in march 2023 and march 2024

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Chronic pain (past 3 months)	Participants will be asked "Have you had constant or frequent pain [most of the day] during the past 3 months?" and asked to identify the average and maximum intensity of pain in that period using a visual analogue scale (VAS) from 0 to 10. Only participants with an average pain of 4 or more will be classified as having significant chronic pain.	Baseline and 12-month follow-up
Depression (2 weeks)	As measured by the Patient Health Questionnaire (PHQ-9). Total scores on the PHQ-9 range from 0 to 27 and higher scores indicate higher symptoms of depression.	Baseline and 12-month follow-up
Anxiety (2 weeks)	As measured by the General Anxiety Disorder (GAD-7). Total scores on the GAD-7 range from 0 to 21 and higher scores indicate higher symptoms of anxiety.	Baseline and 12-month follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Migraine Disability	As measured by the MIDAS (Migraine Disability Assessment). Total scores on the MIDAS range from 0 to 20 and higher scores indicate higher disability.	12-month follow-up
Neuropathic Pain	As measured by the DN4 (Neuropathic pain DN4 Questionnaire). Total scores on the DN4 range from 0 to 10 and Scores ≥ 4/10 indicate neuropathic pain.	Baseline and 12-month follow-up
Fibromyalgia	As measured by the Fibromyalgia Survey Questionnaire (FSQ). The possible score ranges from 0 to 31 points. A score equal to or greater than 13 points is consistent with a diagnosis of fibromyalgia.	12-month follow-up
Self harm (2 weeks)	As measured by item 9 (Thoughts that you would be better off dead or of hurting yourself in some way) of the Patient Health Questionnaire (PHQ-9).	Baseline and 12-month follow-up
Insomnia (2 weeks)	As measured by the Insomnia Severity Index (ISI). Responses can range from 0 to 4, where higher scores indicate more acute symptoms of insomnia.	Baseline and 12-month follow-up
Loneliness	As measured by the 3-item University of California, Los Angeles Loneliness Scale (R-UCLA). Total scores range from 3 to 9 and higher scores indicate higher perceived loneliness.	Baseline and 12-month follow-up

Collaborators and Investigators

• Sponsor: Pontificia Universidad Catolica de Chile
• Collaborators: Chilean Safety Association (ACHS)
• Investigators: Principal Investigator: Antonia Errazuriz, PhD, Pontificia Universidad Catolica de Chile

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2023
• Primary Completion (Actual): April 30, 2025
• Study Completion (Actual): September 25, 2025

Study Registration Dates

• First Submitted: February 5, 2024
• First Submitted That Met QC Criteria: April 3, 2024
• First Posted (Actual): April 8, 2024

Study Record Updates

• Last Update Posted (Actual): December 12, 2025
• Last Update Submitted That Met QC Criteria: December 5, 2025
• Last Verified: January 1, 2024

More Information

Terms related to this study

• Keywords: Depression; Prevalence; Anxiety; Chronic pain; Incidence
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Nervous System Diseases; Muscular Diseases; Mental Disorders; Neuromuscular Diseases; Rheumatic Diseases; Behavioral Symptoms; Peripheral Nervous System Diseases; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Pathological Conditions, Signs and Symptoms; Behavior; Signs and Symptoms; Anxiety Disorders; Fibromyalgia; Chronic Pain; Depression; Neuralgia; Sleep Initiation and Maintenance Disorders; Self-Injurious Behavior
• Other Study ID Numbers: 230602006

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The anonymized database and codebook will be made available to researcher in the Dataverse website
• IPD Sharing Time Frame: Upon first manuscript submission
• IPD Sharing Access Criteria: For researchers
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No