HIV diagnosis metrics
A total of 1590 persons were diagnosed with HIV/AIDS in King County and 368 persons completed the One-on-One program in 2005–2009. summarizes results for indicators of the timing of HIV diagnosis countywide (using eHARS data) and in the One-on-One program (see for metric definitions). Countywide, over the five year period, 15% of newly diagnosed persons had never previously tested for HIV, the median ITI among those who had previously tested was 13 months, and 32% of persons had an AIDS diagnosis within one year of HIV diagnosis (late HIV diagnosis). Compared to non-MSM, MSM were more likely to report having previously tested HIV negative [91% vs. 61%, OR 6.38 (95% CI: 4.33 – 9.41)], had higher CD4 counts at diagnosis (median 399 vs. 220 cells/mm3, p<0.001), lower odds of late HIV diagnosis [26% vs. 46%, OR 0.41 (95% CI: 0.33 – 0.51)], and lower odds of dying with AIDS within one year [1% vs. 4%, OR 0.31 (95% CI: 0.15 – 0.63)]. There were no statistically significant changes in the metrics of timely HIV diagnosis during 2005–2009 countywide or in the One-on-One Program (data not shown).
Metrics of the timing of HIV diagnosis and linkage to HIV care among persons diagnosed with HIV in King County, 2005–2009
As shown in , the ITI was inversely correlated with CD4 count at diagnosis (p<0.001), and longer ITI was associated with higher odds of late diagnosis [OR 1.21 (95% CI: 1.15 – 1.28) per 12 month testing interval]. However, ITI appeared to explain little of the variance in CD4 count at time of diagnosis (R2=0.07), even among cases with confirmed dates of last negative HIV test (). Moreover, of the 257 persons defined as having a late HIV diagnosis with available testing history data, 80 (31%) reported testing HIV negative in the two years prior to their HIV diagnosis. Of 508 persons with late diagnosis, 311 (61%) had AIDS at the time of HIV diagnosis, and 31 (6%) died within the first year. Among the 93 persons with a laboratory-confirmed date of last negative HIV test, nine (10%) had a late HIV diagnosis, five (56%) of whom had tested negative for HIV in the two years preceding diagnosis. Of 1304 persons with complete CD4 data at the time of diagnosis, 894 (69%) had CD4 counts ≤500 cells/mm3 and 638 (49%) had CD4 counts ≤350 cells/mm3.
Correlation between intertest interval (ITI) and CD4 count at diagnosis, and ITI in persons diagnosed with AIDS within one year
Linkage to care metrics
Between 2005 and 2009, 88% of 1590 persons with newly diagnosed HIV in King County linked to care within 3 months of diagnosis (), and that proportion increased over the analysis period (p<0.001). Of the 191 who did not link within 3 months, 125 (65%) had a CD4 count or VL reported 4–56 months after diagnosis. Of the 860 persons diagnosed in 2007–2009 who successfully linked to initial HIV care, 169 (20%) had no additional results reported in the 3–9 months after linkage. Younger age was associated with lower odds of linking to sustained care [OR 0.89 per each 5 year decrease (95% CI: 0.84 – 0.95)], as was having a CD4 count >350 cells/mm3 at diagnosis [77% vs. 84% in those with CD4 ≤350 cells/mm3, OR 0.64 (95% CI: 0.45 – 0.90)]. There were no significant differences in linkage to sustained care by gender, race, or HIV risk factor (data not shown).
At the end of 2009, 6070 diagnosed PLWHA were presumed to reside in King County. shows the completeness of laboratory reporting, virologic suppression, and CD4 count distribution of these persons. Laboratory data were reported in 2009 for 81% of all PLWHA presumed to reside in the area. Among 1123 persons for whom no data were available in 2009, 495 (44%) had not had any data reported to surveillance for over five years (As shows, 429 persons last had a CD4 or VL result reported prior to 2005; 66 persons had no CD4 or VL reported and were diagnosed with HIV prior to 2005). Compared to whites, African-Americans and Latinos were less likely to have had at least one VL reported in 2009 [80% vs. 83%, OR 0.81 (95% CI: 0.68 – 0.96) and 76% vs. 83%, OR 0.66 (95% CI: 0.54 – 0.81), respectively]. The proportion of PLWHA without laboratory data in 2009 did not vary significantly by age, gender or HIV transmission risk factor (data not shown).
Virologic suppression and CD4 count distribution of persons living with HIV/AIDS (PLWHA) presumed to be residing in king County at the end of 2009
Engagement in continuous care
The proportion of PLWHA engaged in continuous care (≥2 visits ≥3 months apart in 2009) depended substantially on the denominator we used to define engagement in care (). Using the denominator of persons who had at least one visit in 2009, excluding those who established care in the second half of the year, which is the Health Resources and Services Administration (HRSA) definition used in the NHAS, 81% (3864/4762) were engaged in continuous care. Using a less restrictive denominator, the total number of PLWHA presumed to reside in King County at the end of 2009 (excluding those who established care in the second half of the year) 66% (3864/5885) were engaged in continuous care. Finally, assuming that persons with no data reported to HIV surveillance for 5 years were no longer in King County at the end of 2009 and thus eliminating them from the denominator, 72% (3864/5390) were engaged in continuous care.
Variation in estimates of engagement in continuous care and viral suppression based on differing denominator definitions
Of persons with at least one VL reported in 2009, 65% had undetectable VL at the time of last report. However, like estimates of engagement in care, estimates of virologic suppression varied substantially based on the denominator used. Including either all PLWHA not known to have died or left the area or all PLWHA for whom laboratory data were reported in the prior 5 years, 53% and 57%, respectively, had an undetectable VL. Among persons with at least one VL reported, compared to whites, African-Americans had lower odds of virologic suppression [62% vs. 66%, OR 0.85 (95% CI: 0.73 – 0.99)], and virologic suppression among Latinos was similar (67% vs. 66%, OR 1.06 (95% CI: 0.86 – 1.30)]. The mean community VL was significantly higher among African-Americans compared to whites (41,497 vs. 17,874 copies/mL, p=0.008), but did not differ significantly between Latinos and whites (14,408 vs. 17,874 copies/mL, p=0.87). While the mean community VL was higher among MSM than non-MSM (20,618 vs. 15,627 copies/mL; p=0.01), the proportions of MSM and non-MSM with virologic suppression did not significantly differ [65% vs. 63%, OR 1.11 (0.94 – 1.30)].
Associations between linkage, engagement, and viral suppression
Of persons diagnosed with HIV in 2007, those who linked to sustained care in the year following their diagnosis were more likely than those who did not link to sustained care to be engaged in continuous care in 2009 [91% vs. 74%, OR 3.65 (95% CI: 1.55 – 8.59)] and more likely to have an undetectable VL at the time of last report [63% vs. 44% of persons with at least one VL reported, OR 2.19 (95% CI: 1.12 – 4.29)]. In contrast, engagement in continuous care and virologic suppression did not differ significantly by linkage status when linkage was defined as completion of a single visit [88% vs. 87%, OR 1.16 (95% CI: 0.25 – 5.46); and 60% vs. 53%, OR 1.32 (95% CI: 0.46 – 3.78, respectively]. Among persons with at least one VL reported in 2009, those engaged in continuous care were more likely to have virologic suppression [69% vs. 58%, OR 1.56 (95% CI: 1.34 – 1.81)] and had a lower mean viral load (14,158 vs. 29,623, p<0.001) than those not engaged in continuous care. Despite this, most persons with only one VL reported to surveillance in 2009 had an undetectable VL.