INTRODUCTION

age increasing the likelihood of progression to a severe level requiring aggressive therapy (4,5).

This study compared retrospectively the demographic, historic, and clinical variables on first presentation and on the consecutive visit in 50 patients with mild and 50 patients with severe disease to determine possible prognosticators of severity in TO.

METHODS

This was a retrospective case–control study using chart review. The charts from 340 new patients consecutively referred to the University of British Columbia Thyroid Orbitopathy Clinic between 1993 and 1996 were separated into two groups based on therapy during the active phase of their disease. At our clinic, we grade the inflammatory activity of thyroid orbitopathy using a clinical activity index similar to that described by Mourits et al. (Table 1). We categorize patients with inflammatory scores less than 4 (out of a possible 8), with no progressive strabismus, and without optic neuropathy, as having mild disease and treat them conservatively with observation, lubricant eye drops, or cool compresses. We define severe disease as including those patients with an inflammatory score of 4 or greater out of 8, with progressive ocular motility restriction, or with optic neuropathy. These patients are offered more aggressive

Table 1 Thyroid Orbitopathy Inflammatory Score

(UBC Thyroid Orbitopathy Clinic)

therapy including systemic anti-inflammatories and=or orbital radiation.

From each of the two groups, 50 patients were randomly selected using a computer-generated sequence and their charts reviewed for differences in symptoms, signs, rate of disease onset, and progression between their first and subsequent visit. Statistical analysis was applied using Student’s t-test, w2-test, and Mann–Whitney U-test.

RESULTS

Demographics

Of the 340 patients initially reviewed, we classified 119 (35%) as having severe disease and 221 (65%) with mild disease. The randomly selected groups of 50 patients each were compared for age, sex, race, family history, and smoking history (Table 2).

The mean age at presentation of patients in the severe group was 55.4 years and in the mild group 39.3 years; this difference was statistically significant (p < 0.0001, Student’s t-test).

The severe group included 73.8% females and 26.2% males, while the mild group had 83% females and 17% males;

Table 2 Demographic Comparison Between Disease Severity Groups (Student’s t- and w2-tests)

regard to racial distribution, with the severe group comprised of 90.5% white and 9.5% other races (Chinese, Indian, Native American Indian, and African) and the mild group comprised of 66% white and 34% others.

A positive smoking history was present in 57.1% of the severe group and 44.7% of the mild group, which was found to be not statistically different (p > 0.05).

A positive family history of thyroid orbitopathy was present in 33.3% of the severe group and 27.7% of the mild group, statistically not different (p > 0.05).

Historical Features

Symptoms of thyroid orbitopathy and systemic thyroid disease were recorded at the initial presentation (Table 3).

Diplopia and lid and conjunctival swelling were reported more frequently in the severe group than in the mild group and found to have a statistically significant difference (p < 0.0005). Orbital pain (including both deep orbital aching as well as foreign body irritation) was reported equally commonly in both groups (p > 0.05).

Table 3 Comparison of Symptoms Between Disease Severity

Groups (w2-test)