The data of the KV include information on physician invoices of each treated case in the time period from 01.01.2003 until 31.12.2004 of all office-based physicians in the government district Dresden. The invoices include data of the patient (insurance number, date of birth, gender, first name, zip code of place of residence, insurance status), the claimed services of each case (disease according to ICD-10, item and point value in the doctors’ fee scale, EBM) as well as information on the provider (e.g. specialty). For the time period from Jan. 1, 2003 and Dec. 31, 2004 the KV possesses data on 2,165,771 patients with about 23 million invoices.
The AOK Saxony provided all corresponding prescription data on all insured patients who were in physicians’ treatment in the years 2003 and 2004 (n = 1,837,783). The data fields contain information on the prescribed medications (anatomic-therapeutic-chemical classification code [ATC], prescribed amount, pharmacy sale prices, date of the prescription), on the prescribing physician (physician number) and on the patient treated (insurance number, year of birth, gender).
By connecting invoice and patient-based reimbursement claims data of the KV with the corresponding prescription data of the AOK it is possible to attain a comprehensive depiction of the actual medical care and pharmacologic therapy in routine outpatient care. The source population of the study collective of patients with AE are 257,347 patients insured by the AOK who were in physicians’ care in the time period 2003/2004 in the government district Dresden.
According to the guideline “Good Practice of Secondary Data Analysis” an a priori internal diagnosis validation was undertaken to avoid misclassification bias. The study evaluation consisted of 11,555 patients where the diagnosis AE (ICD-10: L20) was made at least twice in different quarters in the study period or by at least two different physicians in one quarter. Insured patients for whom the diagnosis AE was encoded only once in the study time period were not included in the analysis, as these were presumably often only suspected diagnoses or diagnoses of exclusion whose consideration in the analysis could lead to systematic errors, e.g. in overestimation of the proportion of patients not treated .
Using this cohort of 11,555 patients with AE we examined:
How often patients were in outpatient treatment due to AE,
Which proportion of patients was cared for by dermatologists, pediatricians, general practitioners or internists and which effect age and gender of the patient had on this,
Which medications were used to treat patients with AE and what effect patient age (categories: 0–2 years; 3–11 years; 12–17 years; 18–64 years; ≥ 65 years) and gender had on this, and
What amounts of anti-inflammatory preparations were prescribed per patient to treat AE.
Anti-eczematous therapies were grouped according to ATC code and analyzed and classified according to groups of the active ingredient. Topical corticosteroids (TCS) were classified according to their antiinflammatory potency using the German classification of Niedner (class I: weak, class II: medium, class III: strong, class IV: very strong) . Systemic corticosteroids are administered for a multitude of other diseases besides AE. Frequent diseases (besides AE) that are typical or common indications for systemic corticosteroids include chronic obstructive pulmonary disease (ICD-10 J44), chronic bronchitis (J42), reactive arthritides (M02), inflammatory polyarthropathies (M05–M14), systemic connective tissue diseases (M30–M36), urticaria (L50), pseudocroup (J38.5), Crohn disease (K50) and ulcerative colitis (K51) . Our goal was a careful estimation of the proportion of patients with AE treated with systemic corticosteroids for the AE. Therefore, it was assumed that the steroid medication was prescribed for AE only in those patients who had none of the above-mentioned competing indications for systemic corticosteroids. All data present cannot be assigned to individual patient so that data protection regulations are observed . For the performance of the present study approval was granted by the responsible ethics commission which also includes all relevant aspects of data protection.