Inter-examiner reliability of the Doha agreement meeting classification system of groin pain in male athletes

Key points

1. 01Kappa values ranged from slight (k=0.13 for 'other causes') to substantial (k=0.62 for hip-related groin pain) across the six clinical entities
2. 02Perfect 100% agreement was achieved for the 7 athletes with unilateral, single-entity groin pain
3. 03Ranking entities by perceived clinical importance improved reliability for adductor-, inguinal-, and iliopsoas-related pain but not for pubic-related or 'other causes'
4. 04Subgroup analysis using strict diagnostic criteria showed higher kappa values (0.23 to 0.73, fair to substantial) compared to the primary analysis (0.12 to 0.57)
5. 05Both examiners were Doha agreement panel experts, so findings may overestimate reliability achievable by less experienced clinicians

How it was conducted

Design

Prospective inter-examiner reliability study

Participants

48 male athletes (66 symptomatic sides) with longstanding groin pain, recruited at Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Qatar

Examiners

Two blinded clinicians: a general surgeon (23 years experience) and a physiotherapist (10 years experience), both Doha agreement panel members

Classification tool

Doha agreement meeting classification system (adductor-, inguinal-, iliopsoas-, pubic-, hip-related groin pain, and other causes)

Primary outcome

Inter-examiner reliability measured by Cohen's Kappa with 95% CI

Analysis

Dichotomous (present/absent) and ordinal (ranked by clinical importance) kappa; subgroup analysis using strict Doha criteria

What they found

• Adductor-related groin pain: kappa 0.40 (95% CI 0.16-0.64), fair; weighted kappa 0.52-0.65 range after ranking
• Inguinal-related groin pain: kappa 0.44 (95% CI not fully reconstructed from text), moderate on dichotomous scale
• Iliopsoas-related groin pain: kappa 0.57 (95% CI 0.37-0.77), moderate on dichotomous scale
• Pubic-related groin pain: kappa 0.12 (95% CI -0.23 to 0.46), slight
• Hip-related groin pain: kappa 0.62 (95% CI 0.30-0.95), substantial
• Other causes of groin pain: kappa 0.13 (95% CI -0.35 to 0.61), slight
• Overall exact agreement on same classification combination: 14/48 participants (29%) and 15/66 sides (23%)
• Unilateral single-entity cases: 100% agreement (7/7 participants)
• Subgroup analysis (strict criteria): kappa 0.48 for inguinal-, 0.49 for adductor-, 0.73 for iliopsoas-, 0.23 for pubic-related groin pain

Limitations

• Both examiners were experienced Doha agreement panel experts, limiting generalizability to clinicians with less groin-pain specialization
• Tertiary referral setting inflated complexity (bilateral pain, multiple entities), which may have reduced reliability compared to primary care
• Study population was exclusively male athletes, so findings cannot be assumed to apply to female athletes
• Small sample for low-prevalence entities (hip-related 11%, other causes 10%), increasing kappa uncertainty

Why it matters

For patients

Athletes with groin pain should know that the label assigned to their condition can differ between clinicians, particularly if pain is present on both sides or involves more than one structure.

For clinicians

When applying the Doha classification, reliability is acceptable for single-entity presentations but clinicians should be cautious interpreting multi-entity or bilateral cases; using strict Doha criteria and ranking by clinical importance improves agreement.

For readers

This is the first study to formally test how consistently the widely used Doha groin classification can be applied, revealing important gaps that need to be addressed before the system can support reliable clinical decision-making or research.