Psychometric properties of the Swedish version of the international outcome inventory – alternative interventions (IOI-AI) – ear surgery (IOI-AI^op)

Figures & data

Table 1. Demographic data.

	All n = 162	STp n = 47	STs n = 29	STq n = 86	p value (chi2, degrees of freedom)	p value (Kruskal-Wallis H, degrees of freedom)
Sex (% female, (n female))	64%	64%	76%	59%	p = 0.28 (2.57, 2)
	(103)	(30)	(22)	(51)
Age at intervention Years (±SD)	49.7	43.7	47.7	54.2		p < 0.001 (22.21, 2)
	(13.4)	(11.0)	(8.9)	(14.1)

Groups: (STp) Stapedotomy, without prior hearing aid use or prior ear surgery – primary intervention; (STs) Stapedotomy, with prior hearing aid use – secondary intervention; (STq) Stapedotomy, included from the Swedish quality register for otosclerosis surgery-quality register.

*For comparisons between groups, the nonparametric Kruskal-Wallis and the chi-square tests were used. Fisher’s permutation test was used for univariate analyses.

Statistically significant differences were observed between all groups regarding age.

(STp versus STs p = 0.050, STp versus STq p < 0.001, STs versus STq p = 0.026).

Table 2. Pure tone audiometry.

Groups	All n = 148		STp n = 38		STs n = 24		STq n = 85
	ST	CL	ST	CL	ST	CL	ST	CL
Pre intervention
PTA4 AC, dB HL (±SD)	54 (15.1)	26 (18.3)	47 (9.2)	15 (14.5)	54 (10.1)	28 (17.7)	56 (17.2)	30 (18.2)
10^th percentile	38	5	35	1	38	5	41	11
50^th percentile	51	21	48	9	52	22	54	26
90^th percentile	71	51	58	35	69	55	84	56
PTA4 BC, dB HL (±SD)	24 (12.1)	19 (12.8)	19 (6.7)	11 (7.1)	20 (8.7)	17 (10.2)	28 (13.4)	22 (14.0)
10^th percentile	11	5	10	4	8	5	12	8
50^th percentile	21	16	18	10	20	15	28	19
90^th percentile	41	39	29	21	28	28	46	41
ABG, dB (±SD)	29 (9.5)	10 (11.2)	27 (7.3)	6 (10.8)	33 (9.0)	11 (12.7)	29 (10.3)	11 (10.7)
10^th percentile	17	−1	16	−2	17	−1	17	1
50^th percentile	28	6	27	2	32	9	27	8
90^th percentile	41	24	36	15	43	26	46	23
Post intervention
PTA4 AC, dB HL (±SD)	31 (14.1)	26 (18.1)	25 (7.7)	14 (12.8)	27 (10,1)	28 (18.7)	35 (15.7)	30 (17.8)
10^th percentile	19	5	16	2	19	8	19	9
50^th percentile	29	24	25	10	25	25	31	30
90^th percentile	49	50	35	34	42	53	59	54
PTA4 BC, dB HL (±SD)	21 (12.8)	19 (13.3)	15 (7.6)	11 (5.9)	18 (9.4)	16 (10.6)	25 (14.0)	24 (14.8)
10^th percentile	9	5	5	2	6	4	10	8
50^th percentile	18	15	15	10	16	14	22	20
90^th percentile	38	36	26	18	26	30	45	48
ABG, dB (±SD)	10 (6.8)	9(10.9)	10 (7.8)	4 (10.6)	9 (4.3)	12 (14.4)	10 (7.0)	10 (8.8)
10^th percentile	3	−1	3	−4	4	−1	3	1
50^th percentile	9	6	9	1	8	6	8	9
90^th percentile	17	24	17	15	15	33	17	23

Groups: (STp) Stapedotomy, without prior hearing aid use or prior ear surgery – primary intervention; (STs) Stapedotomy, with prior hearing aid use – secondary intervention; (STq) Stapedotomy, included from the Swedish quality register for otosclerosis surgery – quality register.

ST = stapedotomy, intervention ear; CL = contralateral ear; PTA₄ mean of frequencies 0.5, 1, 2, and 4 kHz; dB = decibel; HL = hearing level; AC = air conduction; BC = bone conduction; ABG = air-bone gap.

Mean values, standard deviations (SD) and percentiles (10^th, 50^th and 90^th) are presented.

Figure 1. Distribution of the IOI-AI^op responses.

RAL = residual activity limitation; RPR = residual participation restriction; Im on Oth = impact on others; QoL = quality of life.

Each item is scored on a Likert scale ranging from 1 to 5, where 5 represents the most favourable outcome.

Table 3. Item level descriptive data of the IOI-AI^op.

Items	All n = 162	STp n = 47	STs n = 29	STq n = 86
Benefit	3.94 ± 1.35(1–5)	3.79 ± 1.30(1–5)	4.38 ± 1.18(1–5)	3.88 ± 1.4(1–5)
RAL	3.68 ± 1.18(1–5)	3.68 ± 1.02(1–5)	3.66 ± 1.14(1–5)	3.68 ± 1.29(1–5)
Satisfaction	4.4 ± 1.16(1–5)	4.26 ± 1.17(1–5)	4.62 ± 0.90(2–5)	4.40 ± 1.23(1–5)
RPR	4.43 ± 0.89(1–5)	4.38 ± 0.71(2–5)	4.34 ± 0.90(2–5)	4.49 ± 0.97(1–5)
Impact on others	4.33 ± 0.94(1–5)	4.40 ± 0.9(1–5)	4.41 ± 0.82(3–5)	4.26 ± 1.0(1–5)
Quality of life	3.64 ± 1.17(1–5)	3.30 ± 1.05(2–5)	4.10 ± 1.14(2–5)	3.66 ± 1.19(1–5)
Factor 1^op	12.01 ± 3.16(3–15)	11.43 ± 3.05(4–15)	13.10 ± 2.53(6–15)	11.95 ± 3.34(3–15)
Factor 2^op	12.43 ± 2.60(3–15)	12.47 ± 1.97(6–15)	12.41 ± 2.53(7–15)	12.40 ± 2.94(3–25)

Groups: (STp) Stapedotomy, without prior hearing aid use or prior ear surgery – primary intervention; (STs) Stapedotomy, with prior hearing aid use – secondary intervention; (STq) Stapedotomy, included from the Swedish quality register for otosclerosis surgery – quality register.

RAL = residual activity limitation; RPR = residual participation restriction.

Factor 1^op: benefit, satisfaction, QoL; Factor 2^op: RAL, RPR, impact on others.

Mean values are presented with standard deviation (SD) and range.

Each item is scored on a Likert scale ranging from 1 to 5, where 5 represents the most favourable outcome.

Table 4. Principal component analysis of the IOI-AI^op.

	Factor 1^op	Factor 2^op
Benefit	0.88	0.31
RAL	0.62	0.61
Satisfaction	0.82	0.18
RPR	0.11	0.91
Impact on Others	0.26	0.88
QoL	0.81	0.09

Principal component analysis was performed with Varimax rotation and Kaiser normalisation.

Components with an eigenvalue > 1 was extracted.

RAL = residual activity limitation; RPR = participation restriction; QoL = quality of life.

Table 5. Reliability of the IOI-AI^op.

IOI-AI^op subscales	Test (n = 21) (Mean ± SD)	Retest (n = 21) (Mean ± SD)	ICC (95% CI)^a	Internal consistency reliability (95% CI)^b
Factor 1^op	11.3 ± 3.3	11.5 ± 3.3	0.95 (0.89, 0.98)	0.83 (0.78, 0.87)
Factor 2^op	12.3 ± 2.8	12.2 ± 2.6	0.94 (0.87, 0.98)	0.82 (0.76, 0.86)

Groups: (STp) Stapedotomy, without prior hearing aid use or prior ear surgery – primary intervention (n = 47); (STs) Stapedotomy, with prior hearing aid use – secondary intervention (n = 29); (STq) Stapedotomy, included from the Swedish quality register for otosclerosis surgery – quality register (n = 86).

^aTest-retest reliability measured by intraclass correlation coefficient (n = 21).

^bInternal consistency measured by Cronbach’s alpha.

Data availability statement

Data are available from the corresponding author upon reasonable request.