Expanding Outpatient Benefit Package Without Increasing Total Spending: Evidence From Outpatient Benefit Reform for Non-Chronic Disease Patients

China required regions to expand outpatient benefit package since 2021, but whether it may induce moral hazard among non-chronic disease patients remains undetermined. We aimed to clarify effects of expanding outpatient benefit package on health-seeking behaviors, medical expenses and reimbursement of people without chronic disease. This study employed segmented regression of interrupted time series, utilized 5 765 419 non-chronic disease patients’ medical services records from January 2021 to December 2023 in Guangzhou, to analyze influence of expanding outpatient benefit package on non-chronic disease patients. (1) For health-seeking behaviors: monthly medical visits (β 1 + β 3 =0.0069, P = .001) and the monthly number of outpatient visits (β 1 + β 3 =0.0066, P = .001) exhibited a significant increasing long-term trend. This corresponds to significant annual increases of 0.08 per person in both medical and outpatient visits. (2) For medical expenses: the monthly outpatient medical expenses showed a significant upward trend (β 1 + β 3 = 6.9308, P = .002), which was equivalent to a significant increase of 83.17 yuan in outpatient medical expenses per person per year. (3) For expenditures of basic medical insurance funds: expenditure of basic medical insurance funds on outpatient medical services were significantly higher than pre-intervention levels by 35 yuan (β 3 = 2.9169, P = .036), with a sustained significant growth rate of 52.51 yuan per person per year (β 1 + β 3 = 4.3762, P = .004). Monthly outpatient out-of-pocket expenses exhibited a significant instantaneous decrease of 135.27 yuan ( P < .001), followed by a significant upward trend (β 1 + β 3 = 2.5562, P = .038), corresponding to an annual increase of 30.67 yuan per person. Within well-designed payment models, expanding outpatient benefit package among patients without chronic disease could enable them to get a more comprehensive and prompt treatment while total medical expenses and expenditure of the basic medical insurance funds are stable totally.