Reduced referral and case fatality rates for severe symptomatic hyperlactataemia in a South African public sector antiretroviral programme: a retrospective observational study

Table 2 Standard bicarbonate levels and case fatality rates for severe symptomatic hyperlactataemia cases (2003-2008)

Time Period	Number of severe SHL cases	Number who had SHCO₃ performed (%)	Median SHCO₃ (IQR)¹	Number with SHCO₃ level <15 mmol/l (%)²	Number of deaths (case fatality rate as%)³
2003	4	3 (75)	14.2 (5.1-19.8)	2 (66.7)	0 (0)
2004	15	14 (93.3)	15.5 (4.9-18)	7 (50)	5 (33.3)
2005	67	55 (82.1)	17.6 (13.5-20)	19 (34.5)	7 (10.4)
2006	99	89 (89.9)	19.8 (17-21.3)	13 (14.6)	5 (5.1)
2007	53	49 (92.5)	20.1 (18-21.2)	6 (12.2)	3 (5.7)
2008	16	16 (100)	20 (17.3-21.4)	2 (12.5)	0 (0)
Entire period	254	226 (89)	19.1 (15.8-20.9)	49 (21.7)	20 (7.9)

¹ Median standard bicarbonate level: p for trend < 0.001 (for period 2003-2008).
² Proportion with standard bicarbonate < 15 mmol/l: p for trend < 0.001 (for period 2003-2008). The proportion was calculated using the number who had standard bicarbonate performed during that year as denominator, see column 3.
³Case fatality rate: p for trend = 0.002 (for period 2004 - 2008; 2003 was excluded as case fatality rate peaked in 2004).
SHL = Symptomatic Hyperlactataemia, SHCO₃ = Standard bicarbonate in mmol/l (normal range 21-26 mmol/l), IQR = interquartile range.

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