Duration of military service is associated with decision quality in Veterans considering total knee replacement: case series

Figures & data

Table 1 Cohort characteristics based on highest service rank achieved^a

Characteristics	Junior enlisted E1-E4 (n=9)	Senior enlisted/officer E5-E10, O-1 (n=13)	p-value
Age
Mean, Median (SD)	61.6, 63 (8.3)	67.5, 69 (15.1)	0.301^#
IQR (Min-Max)	13 (47–71)	8 (37–85)
Sex
Chi-square value	1.513		0.219^x
Male (%)	8 (89)	13 (100)
Female (%)	1 (11)	0 (0)
Race/Ethnicity
Chi-square value	4.480		0.483^x
White, non-Hispanic (%)	8 (89)	9 (69)
American Indian (%)	0 (0)	1 (8)
Asian or Pacific Islander (%)	0 (0)	1 (8)
Hispanic, Black (%)	0 (0)	1 (8)
Hispanic White (%)	0 (0)	1 (8)
Prefer not to answer (%)	1 (11)	0 (0)
Education
Chi-square value	1.530		0.678^x
High school or less (%)	5 (63)	8 (62)
Bachelor’s degree (%)	2 (25)	3 (23)
Advanced degree (%)	1 (12)	2 (15)
Service characteristics
Active service
Mean, median (SD)	3.7, 2 (0.9)	8.6, 6 (1.9)	0.056^#
IQR (Min-Max)	2 (2–10)	6 (2–23)
Years since discharge
Mean, Median (SD)	36.9, 38 (11.5)	39.2, 47 (19.5)	0.751^#
IQR (Min-Max)	15 (20–52)	33 (6–64)
HK-DQI^b components
Knowledge score
Mean, median (SD)	49%, 40% (18)	45%, 40% (26)	0.673^#
IQR (Min-Max)	20% (20–80)	40% (0–100)
Decision process score
Mean, Median (SD)	38%, 20% (44)	57%, 60% (39)	0.296^#
IQR (Min-Max)	80% (0–100)	60% (0–100)
Concordance score^c
Mean (SD)	44% (53)	38% (51)	0.791^#

Notes: ^xChi-square test. ^#Student's t-test. ^aTotal cohort of 25 patients, 3 patients opted not to report rank. ^bHip and Knee Osteoarthritis Decision Quality Instrument. ^cConcordance score was calculated by a simple match. E1-E4 and E5-E10, O1 refer to military pay codes corresponding to rank. 

Abbreviations: SD, standard deviation; IQR, interquartile range;  Min, minimum; Max, maximum.

Figure 1 Knowledge score distribution within cohort histogram representing the overall breakdown of the total knowledge score of the hip and knee osteoarthritis decision quality instrument (HK-DQI). The greatest number of subjects (8) scored in the 0.6 (or 60%) percentile.

Figure 2 Association of knowledge score and duration of military service correlation plot showing the significant association between increasing total knowledge score with increased number of years served in the military. The R² of 0.36 shows the amount of variance in total knowledge score accounted for by years served in the military. With a p-value of 0.004, this represents a significant association.

Table 2 Service characteristics and HK-DQI results

Exposure	Knowledge score		Concordance		Decision process
	β (regression coefficient)	SE	β	SE	β	SE
Years in service	0.034*	0.012	−0.037	0.041	−0.014	0.029
Years since discharge	<0.001	0.002	−0.001	0.022	−0.003	0.006
Rank of E-5 or Higher	−0.098	0.079	0.050	0.271	0.222	0.445
Graduate degree	0.355*	0.125	0.152	0.132	0.383	0.309

Note: *p-value <0.05. Multivariate regression model measuring characteristics of the veteran cohort and the significant association of each characteristic with respect to the overall scores on the Hip and Knee Osteoarthritis Decision Quality Instrument (HK-DQI). Significant associations are marked with*.