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9th International Workshop on Adverse Drug Reactions and Lipodystrophy in HIV19-21 July 2007, Sydney, Australia |
RISK FACTORS FOR CASE FATALITY: DO WE NEED A NEW CASE DEFINITION FOR SEVERE HYPERLACTATAEMIA IN HIV-INFECTED PATIENTS EXPOSED TO NRTIS?
Antiviral Therapy 2007; 12(Suppl. 2):L24 (abstract no. P-03)
A Arenas-Pinto on behalf of the International Lactic Acidosis Study Group
University College London, London, UK
BACKGROUND: Lactic acidosis (LA) and severe hyperlactataemia (HL) are rare but serious complications of antiretroviral therapy. Most case definitions of HL require symptoms and a raised blood lactate level.
METHODS: In a multinational study to identify risk factors for HL/LA, LA was defined as arterial blood pH<7.35, bicarbonate <20 mmol/l and lactate above normal; HL was defined as confirmed blood lactate >5 mmol/l. Logistic regression was used to identify factors associated with fatality among HL/LA cases.
RESULTS: Among 110 cases most had gastro-intestinal (64.4%) or constitutional symptoms (57.0%) at the time of the event, but 10 (9%) cases were asymptomatic (median lactate 5.8 mmol/l, range 5.1–7.3). The case-fatality rate was 19/110 (17.3%). The median lactate for fatal, non-fatal and all cases was 8.3 mmol/l (IQR 7.2–13.1), 6.4 mmol/l (IQR 5.4–7.8) and 6.7 mmol/l (IQR 5.5–8.1), respectively. After adjusting for current CD4 cell count and dideoxynucleoside exposure, lactate above 7 mmol/l (OR 7.8; 95%CI 1.6–37.8) was independently associated with case fatality. There was some evidence of an association between opportunistic infections and case fatality (OR 3.9; 95%CI 1.0–15.6). None of the asymptomatic cases died as a consequence of the event.
| Table 1. Risk factors for fatality (Abstract P-03) | ||||
| Univariate | Multivariate | |||
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| Variable | OR | 95% CI | OR | 95% CI |
| Blood lactate, mmol/l | ||||
| <7 | 1 | 1 | ||
| 7–10 | 6.4 | 1.6–25.4 | 7.8 | 1.6–37.8 |
| >10 | 12.8 | 2.8–58.2 | 11.0 | 2.0–60.7 |
| Opportunistic infections | 3.8 | 1.3–11.7 | 3.9 | 1.0–15.6 |
| CD4 count <100 | 4.6 | 1.4–15.7 | 3.8 | 0.9–15.9 |
| Exposure to ’drugs’ | ||||
| None | 1 | 1 | ||
| One | 0.4 | 0.1–1.2 | 0.5 | 0.1–2.6 |
| Two | 0.2 | 0.1–0.8 | 0.4 | 0.1–1.9 |
| Symptoms | ||||
| Gastrointestinal | 3.2 | 0.9–12.0 | ||
| Constitutional | 0.9 | 0.3–2.6 | ||
| Acidosis | 1.7 | 0.6–5.2 | ||
| Other | 1.5 | 0.5–4.2 | ||
CONCLUSIONS: Our data suggest that a blood lactate higher than 7 mmol/l is associated with an increased risk of death and may be an appropriate threshold for the diagnosis of severe HL. Patients with confirmed blood lactate above 5 mmol/l may be asymptomatic. Therefore, a case definition based on blood lactate levels might be more appropriate than a definition combining symptoms and lactate values.
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2007-07-24
P-03
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