Table 4.

Health gain (in quality-adjusted life-years) and health system costs saved over the life course from the promotion of smartphone apps for weight loss among the New Zealand population alive in 2011 (population N=4.4 million; 3% discounting; 95% UI in brackets). Results presented for those older than 25 years as relative risks for the associations between risk factors and disease start at age 25 years.

Subpopulation		Non-Māori	Māori	Ethnic groups combined
		QALYsa	QALYs	QALYs	Net costs to the health system (NZ $ million)b
Base-case with no increase in standard downloading of apps (13.5% of exposed population download a weight loss app)
	All	24 (10-47)	5 (2-10)	29 (14-52)	2.3 (1.6-3.0)
	Men	12	2	14	1.1
	Women	12	3	15	1.2
	Per capitac	0.006 (0.005)	0.007 (0.009)	0.007	0.53
	Per capita for those overweight and obesec	0.010 (0.005)	0.011 (0.010)	0.011	0.84
Scenario: 50% increase in standard downloading of apps (20.3% of exposed population download a weight loss app)
	All	37 (15-73)	8 (3-15)	45 (21-81)	2.0 (1.1-2.8)
	Men	18	4	22	1.0
	Women	19	4	23	1.0
	Per capitac	0.010 (0.008)	0.011 (0.014)	0.010	0.46
	Per capita for those overweight and obesec	0.016 (0.007)	0.016 (0.016)	0.016	0.73
Scenario: doubling the standard downloading of apps (27.0% of exposed population download a weight loss app)
	All	49 (19-97)	10 (4-20)	59 (27-107)	1.8 (0.7-2.6)
	Men	24	5	29	0.9
	Women	25	5	30	0.9
	Per capitac	0.013 (0.010)	0.015 (0.018)	0.013	0.40
	Per capita for those overweight and obesec	0.021 (0.009)	0.021 (0.021)	0.021	0.63

^aQALYs: quality-adjusted life-years.

^bIncludes both the cost offsets and intervention cost (see Table 3), distributed pro rata across all people alive in 2011.

^cAll per capita results are QALYs per 1000 adults and NZ $ per adult. Results in brackets for Māori and non-Māori are age-standardized. Results rounded to either 2 or 3 meaningful digits.