Socioeconomic disparities in orthodontic treatment outcomes and expenditure on orthodontics in England’s state-funded National Health Service: a retrospective observational study

Table 3 Treatment outcomes by socioeconomic status (SES)

IMD quintile (reference category: 5 [least deprived])	Mean percentage change
	Model 1: Discontinuation vs. completion n = 19755^a		Models 2 and 3: residual need vs. no residual need
	Model 1: Discontinuation vs. completion n = 19755^a		Among patients who completed n = 14443^b		Among patients who discontinued n = 676^b
	Unadjusted	Adjusted for IOTN AC, gender, age	Unadjusted	Adjusted for IOTN AC, gender, age	Unadjusted	Adjusted for IOTN AC, gender, age
1	6.4	6.1	2.8	2.6	3.5	0.6
2	5.3	5.1	3.3	3.2	−1.6	−1.0
3	3.1	3.1	1.8	1.8	0.3	−0.5
4	1.2	1.1	1.0	1.0	−0.3	−1.2
Missing	3.0	3.0	0.0	−0.3	−10.9	−12.5

AC Aesthetic Component, IMD Index of Multiple Deprivation, IOTN Index of Orthodontic Treatment Need
^aOnly patients with outcome records could be included (4746 had missing outcome records)
^bOnly patients with completed IOTN outcome fields could be included (out of those who completed and discontinued, 3456 and 1180 had incomplete IOTN outcome fields, respectively). The same sample sizes were used for the unadjusted and adjusted analyses (as there were no missing data on gender and age, and a dummy variable was used for the missing IOTN AC data)

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