Determinants of GP billing in Australia: content and time

OBJECTIVE: To examine relations between consultation length and content, and general practitioner choice of claiming level B or C when billing consultations > 20 minutes through Medicare. DESIGN AND SETTING: A secondary analysis from a cross-sectional national general practice survey (1 April 2000 to 31 March 2003) of 101 112 consultations with 2811 GPs, comparing level B consultations 20 minutes (claimed as level B or C), and consultations > 20 minutes claimed as level C with those claimed as level B. MAIN OUTCOME MEASURES: Consultation length, encounter, patient characteristics; number, type of problems managed; type and frequency of treatments provided in relation to consultation level charged. RESULTS: There were 80 476 level B consultations 20 minutes claimed as level B or C (5725 38.4%] level B; 9168 61.5%] level C). Longer level B+C consultations differed from shorter level B consultations in patient sex, Department of Veterans' Affairs card status, and new-patient status, and involved more reasons for encounter, problems managed, chronic problems, clinical treatments, therapeutic procedures, referrals and pathology and imaging orders. Longer consultations claimed as level C were significantly longer (0.9 minutes) than those claimed as level B and involved more reasons for encounter, problems managed (particularly new, chronic, psychosocial and gynaecological) and more clinical treatments. CONCLUSIONS: Patient characteristics and consultation content differ at longer consultations. Consultations charged as level C are more complex than those charged as level B. GPs use both time and content when choosing item number, rather than relying only on specified time thresholds. This has implications for future restructuring of MBS attendance items.