J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website http://www.jocmr.org

Original Article

Volume 5, Number 2, April 2013, pages 101-111

The Use of GDS-15 in Detecting MDD: A Comparison Between Residents in a Thai Long-Term Care Home and Geriatric Outpatients

Figure 1. The plots of Scree Parallel (Left) and Scree Simulation (right) from parallel analysis. The Scree Parallel plot graphs the observed and estimated eigenvalues. Red indicates observed eigenvalues (4.5068 for Factor I and 2.3169 for Factor II), green indicates 95th percentile random data eigenvalues, and gray indicates mean of the random data eigenvalues. The lines intersect denotes the number of factors that must be retained according to the parallel analysis criterion. The lines cross at the second principal component. The Left graph is a summary of the Right, which provides greater detail on the simulation process. The Scree simulation plot demonstrates the Scree plot of the observed eigenvalues and all the Scree plots resulting from the simulated data (shown as a blue stripe). In this dataset, Factor I and Factor II are retained, factor III onwards have Eigen values less than that from simulations, and are therefore rejected.

**Table 1.** Clinical Characteristics of the Sample
	Outpatients’ group (n = 156)	LTC group (n = 81)	All (n = 237)	Statistic	P-value
*Fisher Exact; †diagnosis made by MINI; LTC: long-term care facility; SD: standard deviation; TGDS: Thai version of Geriatric Depression Scale; MMSE: Mini-Mental State Examination.
Age, Mean ± SD	68.83 ± 6.04	76.50 ± 7.28	71.45 ± 7.43	t = 8.61	< 0.0001
Gender, %female	106 (67.9)	45 (55.6)	151 (63.7)		0.021*
Marital Status: living with spouse, n (%)	79 (50.6)	6 (7.1)	35 (14.8)		< 0.0001*
Education (years, Mean ± SD)	3.30 ± 3.33	3.52 ± 3.56	3.46 ± 3.37	t = 0.465	0.643
MDD†, n (%)	68 (43.6)	23 (28.4)	91 (38.4)		0.088*
MDD: %Male:%female	12.2:34.1	10:19	11.4:27.0
Cognitively impaired by MMSE, n (%)	0 (0)	28 (34.6)	-
MMSE, Mean ± SD (Min-Max)	23.96 ± 4.76 (10 - 36)	18.18 ± 6.98 (3 - 36)	23.46 ± 4.81 (10 - 36)	t = 7.53	< 0.0001
TGDS-15, Mean ± SD	5.27 ± 3.78	8.59 ± 2.80	6.41 ± 3.82	t = 6.43	< 0.0001

Table 1. Clinical Characteristics of the Sample

Outpatients’ group
(n = 156)

LTC group
(n = 81)

All
(n = 237)

Statistic

P-value

*Fisher Exact; †diagnosis made by MINI; LTC: long-term care facility; SD: standard deviation; TGDS: Thai version of Geriatric Depression Scale; MMSE: Mini-Mental State Examination.

Age, Mean ± SD

68.83 ± 6.04

76.50 ± 7.28

71.45 ± 7.43

t = 8.61

< 0.0001

Gender, %female

106 (67.9)

45 (55.6)

151 (63.7)

0.021*

Marital Status: living with spouse, n (%)

79 (50.6)

6 (7.1)

35 (14.8)

< 0.0001*

Education (years, Mean ± SD)

3.30 ± 3.33

3.52 ± 3.56

3.46 ± 3.37

t = 0.465

0.643

MDD†, n (%)

68 (43.6)

23 (28.4)

91 (38.4)

0.088*

MDD: %Male:%female

12.2:34.1

10:19

11.4:27.0

Cognitively impaired by MMSE, n (%)

0 (0)

28 (34.6)

MMSE, Mean ± SD (Min-Max)

23.96 ± 4.76 (10 - 36)

18.18 ± 6.98 (3 - 36)

23.46 ± 4.81 (10 - 36)

t = 7.53

< 0.0001

TGDS-15, Mean ± SD

5.27 ± 3.78

8.59 ± 2.80

6.41 ± 3.82

t = 6.43

< 0.0001

**Table 2.** GDS-15 Outcomes for the Outpatients’ Clinic and LTC Home Among Samples Without Cognitive Impairment
Setting	N	Alpha	AUC	95% Confidence Interval	Cut-off	Sensitivity	Specificity	Youden’s Index
LTC: long term care facility; AUC: area under curve; *The best cut-off score as suggested by Youden’s index.
Outpatients’ Clinic	156	0.84	0.96	0.93	0.98	≥ 4	95	75	0.70
						≥ 5*	92	87	0.80
						≥ 6	86	91	0.77
LTC home	53	0.7	0.82	0.69	0.94	≥ 8*	100	49	0.49
						≥ 9	80	65	0.45
						≥ 10	60	84	0.44
All cases	209	0.82	0.88	0.83	0.92	≥ 6	93	63	0.57
						≥ 7*	88	75	0.63
						≥ 8	79	81	0.59

Table 2. GDS-15 Outcomes for the Outpatients’ Clinic and LTC Home Among Samples Without Cognitive Impairment

Setting

Alpha

AUC

95% Confidence Interval

Cut-off

Sensitivity

Specificity

Youden’s Index

Lower Bound

Upper Bound

LTC: long term care facility; AUC: area under curve; *The best cut-off score as suggested by Youden’s index.

Outpatients’ Clinic

156

0.84

0.96

0.93

0.98

≥ 4

0.70

≥ 5*

0.80

≥ 6

0.77

LTC home

0.7

0.82

0.69

0.94

≥ 8*

100

0.49

≥ 9

0.45

≥ 10

0.44

All cases

209

0.82

0.88

0.83

0.92

≥ 6

0.57

≥ 7*

0.63

≥ 8

0.59

**Table 3.** Exploratory Factor Analysis Using TGDS-15: Two-Factor Solution (n = 209)
Item no.	TGDS item	h²	Factor I	Factor II
h²: communality loading coefficient less than 0.1 are not shown; TGDS: Thai version of Geriatric Depression Scale.
14	Feel that situation is hopeless	0.689	0.828	0.184
8	Feel helpless	0.675	0.821	0.164
12	Feel pretty worthless	0.693	0.817	0.284
4	Often get bored	0.556	0.745	0.134
3	Feel that life is empty	0.459	0.661	0.250
6	Afraid something bad is going to happen	0.417	0.621
2	Have dropped many activities and interests	0.301	0.547	0.123
10	More problems with memory than most	0.195	0.432	0.160
15	Feel that most people are better off than me	0.045	0.184
11	Think it is (not) wonderful to be alive	0.557	0.183	0.743
7	Feel (not) happy most of the time	0.62	0.387	0.738
5	(Not) in good spirits most of the time	0.557		0.718
1	Basically (not) satisfied with my life	0.512		0.699
13	Feel (not) full of energy	0.468	0.244	0.669
9	Prefer staying home to going out	0.24	0.304	0.428
	Eigenvalue		4.623	2.360
	Cumulated total explained, %		30.82	15.73
	Cronbach’s alpha, overall = 0.82		0.82	0.76

Table 3. Exploratory Factor Analysis Using TGDS-15: Two-Factor Solution (n = 209)

Item no.

TGDS item

h²

Factor I

Factor II

h²: communality loading coefficient less than 0.1 are not shown; TGDS: Thai version of Geriatric Depression Scale.

Feel that situation is hopeless

0.689

0.828

0.184

Feel helpless

0.675

0.821

0.164

Feel pretty worthless

0.693

0.817

0.284

Often get bored

0.556

0.745

0.134

Feel that life is empty

0.459

0.661

0.250

Afraid something bad is going to happen

0.417

0.621

Have dropped many activities and interests

0.301

0.547

0.123

	Gender								Education								Age
	uniform				non-uniform				uniform				non-uniform				uniform				non-uniform
Item	OR	γ²	df	Sig.	OR	γ²	df	Sig.	OR	γ²	df	Sig.	OR	γ²	df	Sig.	OR	γ²	df	Sig.	OR	γ²	df	Sig.
Bold figures: Statistically significant, meets DIF criteria; OR: Odds Ratio; γ²: Wald Statistic; Df: Degrees of freedom; Sig: Significance level.
1	1.528	35.229	2	0.214	0.969	35.343	3	0.738	0.916	34.003	2	0.658	1.015	34.073	3	0.791	2.21	37.435	2	0.018	1.082	38.036	3	0.446
2	0.418	62.254	2	0.018	1.039	62.382	3	0.719	1.266	57.449	2	0.259	1.033	57.716	3	0.606	0.562	55.941	2	0.103	0.83	59.07	3	0.071
3	0.391	93.18	2	0.699	0.955	93.28	3	0.754	1.118	92.68	2	0.644	1.035	92.837	3	0.692	1.187	90.082	2	0.661	1.023	90.103	3	0.885
4	1.059	93.611	2	0.886	1.102	94.195	3	0.44	1.332	95.316	2	0.227	0.933	96.035	3	0.401	0.4	96.09	2	0.023	0.885	96.811	3	0.384
5	0.848	29.668	2	0.613	0.932	30.29	3	0.436	1.109	29.555	2	0.591	0.931	31.244	3	0.198	1.874	30.769	2	0.055	1.065	31.191	3	0.521
6	1.558	51.76	2	0.216	0.934	52.195	3	0.516	1.573	54.651	2	0.036	0.998	54.653	3	0.97	0.336	59.46	2	0.004	0.986	59.474	3	0.907
7	1.086	103.007	2	0.84	1.066	103.231	3	0.633	1.026	102.619	2	0.915	0.93	103.351	3	0.397	1.511	100.172	2	0.296	0.991	100.176	3	0.949
8	3.198	127.321	2	0.035	0.967	127.338	3	0.898	0.985	122.761	2	0.957	1.006	122.762	3	0.966	1.014	120.649	2	0.976	0.808	121.529	3	0.335
9	0.773	54.537	2	0.476	1.002	54.538	3	0.983	0.788	55.609	2	0.256	0.975	55.769	3	0.69	0.71	54.268	2	0.344	0.997	54.268	3	0.982
10	1.479	49.858	2	0.257	0.793	54.54	3	0.045	1.013	48.782	2	0.948	1.008	48.8	3	0.891	0.925	48.468	2	0.82	0.945	48.468	3	0.585
11	0.646	64.51	2	0.24	0.904	65.295	3	0.386	0.805	64.01	2	0.321	1.023	64.12	3	0.741	2.097	64.796	2	0.04	1.333	69.117	3	0.061
12	1.104	157.542	2	0.864	1.471	158.994	3	0.213	0.812	158.306	2	0.528	0.761	159.949	3	0.202	1.183	155.716	2	0.745	0.743	156.511	3	0.362
13	0.801	66.64	2	0.542	0.912	67.308	3	0.424	0.987	66.529	2	0.952	1.059	67.289	3	0.385	1.558	64.896	2	0.215	0.825	68.037	3	0.071
14	5.169	66.64	2	0.01	1.242	67.308	3	0.483	0.66	140.373	2	0.194	0.793	141.911	3	0.216	0.581	137.781	2	0.282	1.83	139.795	3	0.23
15	0.967	9.336	2	0.922	0.99	9.349	3	0.907	0.982	9.412	2	0.929	1.016	9.495	3	0.773	0.998	8.495	2	0.995	1.146	10.276	3	0.196