This retrospective study estimated that the new American Academy of Ophthalmology guidelines for hydroxychloroquine toxicity screening, which emphasize the use of multifocal electroretinography (mfERG) spectral domain (SD) OCT and/or fundus autofluorescence (FAF) will raise screening costs without improving the rate of detection. Furthermore, the guidelines often are not followed.
The 2011 guidelines recommend a baseline examination at the onset of therapy that includes macular static perimetry and at least one of the following, if available: multifocal mfERG, SD-OCT or FAF. Follow-up examinations are recommended starting after five years of therapy for low-risk patients and annually for high-risk patients. The guidelines call for a daily dose of 400 mg of hydroxychloroquine and around 6.5 mg/kg/d of hydroxychloroquine for individuals of short stature, calculated on the basis of ideal body weight.
The authors evaluated the impact of the new 2011 guidelines on detection of hydroxychloroquine toxicity in practice, ophthalmologists' actions relative to hydroxychloroquine treatment, and screening costs. They reviewed charts from the private practices of 29 doctors. Their final analysis was based on data from 183 patients screened at follow-up examinations and 36 patients screened at baseline.
They estimated that if followed in the manner of the clinicians sampled in this study, the new screening guidelines would result in a 40 percent increase? in screening costs, to $40.7 million, without increasing toxicity detection. The revised guidelines potentially increase the costs of screening patients by 93 percent if both mfERG and SD-OCT are routinely used and more if FAF is also used. Although the guidelines endorse the use of FAF testing, no clinician in this sample did so. A survey of the clinicians suggested that lack of familiarity with the interpretation of FAF images was the reason for this.
Although testing for toxicity using patient height, weight and daily dose is recommended in the guidelines, height, weight and daily dose were not determined in 35.1 percent, 38.4 percent and 26.9 percent of the patients, respectively. The clinicians sampled claimed to be aware of the guidelines and suggested that oversight was the reason behind omitting any dosage, height, weight and duration information from the medical records. The authors say the use of a checklist could avoid this problem.
They also note that although both the 2002 and 2011 guidelines allow for a five-year period without screening for low-risk patients, clinicians largely ignore this provision. Furthermore, approximately half of the scheduled follow-up examinations were for six months rather than the 12 months recommended by both the 2002 and 2011 guidelines for patients after the fifth year of hydroxychloroquine use, even though those scheduled for six-month follow-ups were not at higher risk for toxicity. They write that in an environment of cost constraints, greater frequency of screening of low-risk patients above that recommended may need to be discouraged.
They conclude that these data raise questions that have not been posed before and suggest answers that challenge some of the recommendations of the revised guidelines. Further studies from larger and more diverse samples of screening clinicians would be useful in refining guidelines for hydroxychloroquine screening in times when scarce economic resources need to be allocated based on demonstrated rather than hypothesized value.