Incidence and Prevalence of Scleritis and Episcleritis In Veterans Affairs Medical Centers of the Pacific Northwest

ASCRS 2008 - Chicago

Michael Lloyd, MD, Eric B. Suhler, MD, MPH

Dept of Ophthalmology, Portland VA Medical Center

Casey Eye Institute, OHSU, Portland Oregon

Epidemiology of Uveitis

Epidemiology is the study of factors leading to disease in populations. It serves as the foundation and logic of interventions made in the interest of public health.

Although rare, scleritis is a significant public health problem because:

-It can be the presenting sign of life- and sight-threatening disease

- it is associated with high rates of vision loss (9% with diffuse, 26% with nodular, 74% with necrotizing, and 84% with posterior scleritis)

-30% of people with necrotizing scleritis will be dead within 8 years of presentation without treatment

Introduction

Introduction

There is no population-based literature on the epidemiology of scleritis, but a few referral-based studies exist

Williamson 1974 – 8 years at Southern General Hospital in Glasgow

8 scleritis cases out of 9600 new referrals

Watson and Hayreh 1976 – 10 years at Moorfields

207 episcleritis and 159 scleritis cases in 10 years of a special scleritis clinic

Foster 1993 – 11 years at Mass Eye and Ear94 episcleritis and 172 scleritis cases out of

6600 new referrals

Methods

We sought to ascertain the incidence and prevalence of scleritisvia by a large, population-based study using the VA centralized database (CHIPS) as our model

We searched for any encounter within FY04 coded for scleritis or episcleritis at any VAMC in Oregon or Washington state

Each case was independently reviewed by an ophthalmologist using standardized criteria to document location, onset, continuity, laterality, and associated diagnoses according to the SUN criteria

Jabs et al, AJO 1995

Questionable cases were reviewed by a second ophthalmologist specializing in uveitis

Methods

Scleritis cases had to have some combinationof pain, scleral injection, edema, or thinning.

Episcleritis cases required episcleral injection and discomfortand could not be associated with discharge.

Methods

A case that had active disease which was well controlled with medication would be included as prevalent

Cases with documented inflammation in the past,but no current therapy or inflammation during the study period were classified as “inactive prevalent” and not included in the calculations

Cases with inadequate documentation in any areawere classified as “indeterminate” and not includedin the calculations

Results

Total population surveyed – 152,267

Cases with ICD9 codes reviewed - 519

Incident scleritis cases in FY04 – 2 (1.3 cases/100,000 person-years)

Prevalent scleritis cases in FY04 – 12 (7.88 cases/100,000 population)

Incident episcleritis cases in FY04 – 12 (7.22 cases/100,000 person-years)

Prevalent episcleritis cases in FY04 – 19 (12.48 cases/100,000 population)

Cases by age group and gender

Results

25-44 45-64 65+ Total

Incident

Prevalent Incident Prevalent Incident Prevalent Incident Prevalent

M 0 1 2 5 0 5 2 11

F 0 0 0 1 0 0 0 1

Total 0 1 2 6 0 5 2 12

Episcleritis – average age 54 25-44 45-64 65+ Total

Incident

Prevalent Incident Prevalent Incident Prevalent Incident Prevalent

M 2 4 4 8 4 4 10 16

F 0 0 2 3 0 0 2 3

Total 2 4 6 11 4 4 12 19

Scleritis – average age 61

Number of associated disorders

ScleritisAssociated Disorder

Number of

patients

Rheumatoid Arthritis 3

Anklyosing Spondylitis 1

Gout 1

Polymyalgia rheumatica 1

Fibromyalgia* 1

idiopathic 5

Episcleritis

Associated Disorder

Number of patients

idiopathic 19

Results

*not known to be reported as associated with scleritis

This is the first population-based study to describe the epidemiology of scleritis and episcleritis

There are some weaknesses in our study

-difficulty in diagnosing episcleritis second hand

- still likely to underestimate episcleritis cases

-homogeneous population does not reflect the wider public health (elderly white men are

over- represented)

-documentation was insufficient to further classify cases into diffuse, nodular, necrotizing, etc

Discussion

Our data confirm the behavior of scleritis andepiscleritis as two different disorders.

-Although rare, scleritis tends to be more chronic and is much more likely to be associated with a systemic autoimmune disorder (50% of cases)

-Episcleritis is more common, but shorter-lived; no “progression” was noted from episcleritis to

scleritis

- Likely more frequent in women; more frequent in the 45-65 age group with scleritis occurring in a slightly older population

Discussion

References

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