Evidence-based perspectives on the implementation of screening for neurocognitive impairment in HIV

Figures & data

Table 1 Subtests of the HIV Dementia Scale and International HIV Dementia Scale

HIV Dementia Scale^Citation87			International HIV Dementia Scale^Citation97
Subtest	Cognitive domain assessed	Possible score	Subtest	Cognitive domain assessed	Possible score
Recall of four items at 5 minutes	Recall memory	4	Recall of four items at 5 minutes	Recall memory	4
Timed written alphabet	Psychomotor speed	6	Finger tapping	Motor speed	4
Cube copy	Visuospatial/constructional	2	Fist–palm–side test (Luria test)	Psychomotor speed and executive function	4
Antisaccadic errors	Attention	4
Maximum score		16	Maximum score		12
Score required for positive test		≤10	Score required for positive test		≤10

Table 2 Summary of three meta-analyses of the accuracy of the HDS and IHDS

Reference	Standard diagnosis	Studies pooled	Pooled sensitivity (%)	Pooled specificity (%)	Positive likelihood ratio^a	Negative likelihood ratio^a
HDS studies
Hu et al^Citation91	All HAND	7 (648)	61	79	2.90	0.49
Zipursky et al^Citation90	All HAND	8 (1,338)	48	ND	^b	^b
Haddow et al^Citation89	MND or HAD	10 (2,291)	42	91	4.77	0.64
Haddow et al^Citation89	HAD	13 (1,277)	68	78	3.08	0.41
IHDS studies
Hu et al^Citation91	All HAND	5 (296)	64	59	1.56	0.61
Zipursky et al^Citation90	All HAND	4 (457)	62	ND	^b	^b
Haddow et al^Citation89	MND or HAD	11 (416)	64	66	1.89	0.54
Haddow et al^Citation89	HAD	5 (808)	74	55	1.64	0.47

Notes: ^aPositive likelihood ratio = sensitivity/(1–specificity) and negative likelihood ratio = (1–sensitivity)/specificity. ^bZipursky et al did not present a pooled specificity rate; therefore, likelihood ratios could not be calculated.

Abbreviations: HAD, HIV-associated dementia; HAND, HIV-associated neurocognitive disorder; HDS, HIV Dementia Scale; IHDS, International HIV Dementia Scale; MND, minor neurocognitive disorder; ND, not done.

Table 3 Calculation of posttest probability of HAND using the HDS and IHDS, under three different fictional scenarios

Scenario	Assumed pretest probability (%)	Pretest odds	Test and result^a	Posttest odds	Posttest probability (%)
Higher prevalence screening	33.3	0.5 (2:1 against)	HDS positive	1.5	60
			IHDS positive	0.8	44.4
			HDS negative	0.25	20
			IHDS negative	0.3	23.1
Clinical suspicion	66.7	2.0 (2:1 on)	HDS positive	6.0	85.7
			IHDS positive	3.2	76.2
			HDS negative	1.0	50
			IHDS negative	1.2	54.5
Lower prevalence screening	10	0.111 (9:1 against)	HDS positive	0.333	25
			IHDS positive	0.178	15.1
			HDS negative	0.0556	5.3
			IHDS negative	0.0667	6.2

Note: ^aAssumptions in the table are that positive likelihood ratios are 3.0 for the HDS and 1.6 for the IHDS and that negative likelihood ratios are 0.5 for the HDS and 0.6 for the IHDS. These assumptions are approximations of the results of published meta-analyses,^89–91 rounded off for easier arithmetic.

Abbreviations: HAND, HIV-associated neurocognitive disorder; HDS, HIV Dementia Scale; IHDS, International HIV Dementia Scale.

Table 4 Summary of results from studies of diagnostic accuracy of the MoCA at standard cutoff (26 points)

Country and citation	Sample size	Sensitivity (%)	Specificity (%)	Positive LR^b	Negative LR^b	DOR
South Africa and USA^Citation108	156	89–100^a	22	1.14	0.50	2.28
USA^Citation109	100	85	40	1.42	0.38	3.78
The Netherlands^Citation110	102	56	63	1.51	0.70	2.17
USA^Citation111	200	63	7l	2.17	0.52	4.17
USA^Citation112	67	50	85	3.33	0.59	5.67
South Korea^Citation113	194	53	73	1.99	0.64	3.10

Notes: ^aRange of sensitivity estimates relates to differing thresholds in the gold standard diagnosis. ^bPositive likelihood ratio = sensitivity/(1–specificity) and negative likelihood ratio = (1–sensitivity)/specificity.

Abbreviations: DOR, diagnostic odds ratio; LR, likelihood ratio; MoCA, Montreal Cognitive Assessment.

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