Introduction: Seasonal allergic conjunctivitis (SAC) is a highly prevalent condition that exacts a range of costs from its sufferers. The aim of this study was to examine quality of life (QoL) and economic consequences of SAC amongst private health care patients in Spain.
Methods: 201 sufferers of SAC and 200 controls were recruited from four private eye clinics and one public hospital in five Spanish cities: Alicante, Madrid, Albacete, Las Palmas de Gran Canarias and Valladolid. Participants were between 10 and 80 years of age and Spanish speaking. All potential participants were asked selected questions and sorted into one of the two groups or excluded. Sufferers were administered a set of four questionnaires by researchers consisting of the EQ-5D Health Questionnaire, the National Eye Institute (US) Visual Functioning Questionnaire 25 (VFQ-25), the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and a Health Economic and Demographic Questionnaire (HEDQ). Control participants self-administered the full EQ-5D and VFQ-25 and abbreviated versions of the RQLQ and HEDQ.
Results: The groups were comparable in terms of age and sex, but sufferers had a significantly higher hourly income than controls (p = 0.02). Sufferers exhibited a significantly higher incidence of asthma, nasal symptoms, perennial allergic conjunctivitis, food allergies and other allergies (p < 0.01 for all comorbidities). Sufferers returned significantly lower quality of life scores than controls in all EQ-5D domains other than mobility (p = 0.14). SAC VFQ-25 scores were significantly less than in controls in the overall vision (p < 0.01), distance vision (p < 0.01), ocular pain (p < 0.01), mental health (p = 0.01), role limitations (p < 0.01), and dependency (p = 0.01) domains. Mean scores for the activity domain of the RQLQ were greater in the sufferer group than the control group (P < 0.01) . The total mean per-sufferer cost of SAC amongst our sample of private patients was 348.50 Euros.
Discussion: Sufferers experienced QoL reductions in general health and specific aspects of vision as a result of their SAC. In relative terms, the per-capita economic cost of the condition was higher than in a previous public health care study. This was ascribed to sufferers' willingness-to-pay for symptom alleviation. The unexpectedly high expenditure of the proportion of SAC sufferers who receive private health care serves to highlight the importance of SAC as a costly condition. It also illustrates the need to account for both private and public heath care modalities when attempting to ascribe a total cost to a medical condition.