How many runners with new-onset Achilles tendinopathy develop persisting symptoms? A large prospective cohort study

Key points

1. 0132% of runners with new-onset Achilles tendinopathy reported persisting symptoms at 1-year follow-up
2. 02Higher running distance per week before onset was associated with a lower risk of persisting symptoms (OR 0.9, 95% CI [0.9;1.0])
3. 03Metabolic disorders showed a positive trend toward increased risk of persisting symptoms (OR 5.7, 95% CI [0.9;36.2]), though not statistically significant
4. 0464% of runners scored below 97 on the VISA-A scale at 1 year, suggesting more functional limitation than self-report alone captures
5. 05One quarter (23%) of runners still had to adjust their running activities due to AT symptoms at 1-year follow-up

How it was conducted

Design

Prospective cohort study (1-year follow-up of the INSPIRE trial, Netherlands)

Participants

100 runners with self-reported new-onset Achilles tendinopathy from 1929 INSPIRE trial participants

Recruitment

Runners registering for a Dutch running event (5-42.2 km), October 2016 to April 2017

Follow-up

1-year questionnaire sent after the running event; 62 of 100 runners (62%) responded

Primary outcome

Percentage of runners with persisting Achilles tendinopathy symptoms at 1 year (single yes/no question)

Secondary outcomes

Symptom severity (VISA-A score), course of symptoms, healthcare consumption, running activity, and prognostic factors via multivariable logistic regression

What they found

• 32% of runners (20/62) reported persisting symptoms at 1-year follow-up
• Mean VISA-A score at 1 year was 85.1 (SD 17.9); 64% scored below the 97-point healthy-runner threshold
• Higher running distance per week before onset was associated with lower risk of persisting symptoms: OR 0.9, 95% CI [0.9;1.0], p < 0.05
• Metabolic disorders (hypertension, hypercholesterolemia, diabetes) showed a non-significant trend toward persisting symptoms: OR 5.7, 95% CI [0.9;36.2]
• 56% of runners visited a medical professional over the follow-up year; physiotherapist most common (48%), median 5.0 visits (IQR 5.0)
• 66% of runners adjusted running activities after AT onset; 23% still adjusted activities at 1-year follow-up
• Runners with persisting symptoms decreased distance from median 20.0 km/week to 15.0 km/week (p = 0.041); pace did not change significantly (p = 0.329)
• Runners who recovered slowed pace significantly from 5.0 to 6.0 min/km (p = 0.030); distance did not change significantly (p = 0.912)
• No statistically significant associations found for sex (OR 2.8, 95% CI [0.7;11.5]), age (OR 1.0, 95% CI [0.9;1.1]), BMI (OR 1.2, 95% CI [0.9;1.7]), running experience, previous AT (OR 2.6, 95% CI [0.6;11.2]), or adjusted running activity (OR 0.8, 95% CI [0.2;3.1])

Limitations

• Response rate was only 62%; responders were on average 5.2 years older and more likely to have registered for a full marathon, limiting generalisability to younger and shorter-distance runners
• Injury type (insertional vs midportion) could not be distinguished via the online questionnaire, as no validated questionnaire-based approach exists for this
• Recall bias is possible, especially for presence of metabolic disorders; no physical examination or blood tests were performed, so undiagnosed metabolic disorders may have been present in both groups
• Small number of runners with persisting symptoms limits statistical power and may prevent detection of weaker prognostic associations

Why it matters

For patients

Runners who develop Achilles tendinopathy should know that about one third will still have symptoms a year later, and many will need to adjust their training long-term.

For clinicians

Higher pre-injury weekly running distance may be protective against chronicity, while metabolic comorbidities (hypertension, hypercholesterolemia, diabetes) warrant screening and may warrant closer follow-up.

For readers

This is the first prospective study to quantify the 1-year prognosis of new-onset Achilles tendinopathy in a running cohort, providing a baseline for future prognostic research.