Efficacy and Tolerability of Probenecid as Urate-lowering Therapy in Gout; Clinical Experience in High-prevalence Population

Article Figures & Data

Table 1.

Clinical characteristics

Characteristic	All, n = 57	Probenecid Monotherapy, n = 30	Combination Therapy, n = 27	p^*
Age, yrs, mean (SD)	57 (16)	59 (17)	54 (14)	0.23
Male, n (%)	44 (77)	17 (57)	27 (100)	< 0.001
Ethnicity, n (%)
Maori or Pacific	31 (54)	15 (50)	16 (59)	0.48
Non-Polynesian	26 (46)	15 (50)	11 (40)
Tophaceous gout, n (%)	34 (60)	16 (53)	18 (67)	0.31
Serum creatinine, μmol/l, mean (SD)	114 (32)	110 (33)	117 (31)	0.41
eGFR, ml/min/1.73 m², mean (SD)	61.0 (20.2)	59.7 (19.6)	62.4 (21.1)	0.61
Baseline serum urate, mmol/l^**	0.60 (0.09)	0.58 (0.09)	0.63 (0.09)	0.041
Allopurinol dose, mg/day, mean (SD)	—	0 (0)	362 (124)	< 0.001
Serum urate on allopurinol monotherapy, mmol/l, mean (SD)	—	—	0.50 (0.11)	—
Probenecid dose, g/day, mean (SD)	1.15 (0.59)	1.29 (0.68)	0.99 (0.44)	0.056

↵* Probenecid monotherapy vs combination therapy.
↵** Prior to starting any urate-lowering therapy. eGFR: estimated glomerular filtration rate.

Table 2.

Changes in serum urate concentrations.

	All Patients				Patients with eGFR < 50 ml/min/1.73 m²
	All, n = 57	Probenecid Monotherapy, n = 30	Combination Therapy, n = 27	p^*	All, n = 15	Probenecid Monotherapy, n = 9	Combination Therapy, n = 6	p^*
Final serum urate, mmol/l, mean (SD)	0.39 (0.09)	0.41 (0.09)	0.38 (0.10)	0.24	0.39 (0.09)	0.42 (0.08)	0.34 (0.05)	0.06
No. (%) achieving target serum urate < 0.36 mmol/l	20 (35)	10 (33)	10 (37)	0.77	5 (33)	2 (22)	3 (50)	0.3
Mean change in serum urate from baseline, mmol/l (SD)	0.21 (0.11)	0.17 (0.11)	0.25 (0.10)	0.004	0.18 (0.11)	0.16 (0.13)	0.22 (0.08)	0.38
Mean percentage change in serum urate from baseline (SD)	33.7 (16.6)	28.6 (17.1)	39.3 (14.4)	0.01	30.9 (16.6)	26.1 (18.0)	38.1 (12.6)	0.18
Mean change in serum urate from allopurinol monotherapy, mmol/l, (SD)	NA	NA	0.12 (0.10)	—	NA	NA	0.11 (0.10)	—
Mean percentage change in serum urate from allopurinol monotherapy (SD)	NA	NA	23.8 (16.4)	—	NA	NA	23.0 (15.8)	—

↵* Probenecid monotherapy vs combination therapy. eGFR: estimated glomerular filtration rate.

Table 3.

Logistic regression analysis of predictors of target serum urate < 0.36 mmol/l (n = 57).

Variables	B	SE	p
Allopurinol dose	0.003	0.002	0.198
Probenecid dose	0.573	0.575	0.319
Baseline serum urate	−8.950	4.243	0.035
Non-Polynesian ethnicity	1.279	0.656	0.051
Estimated glomerular filtration rate	0.017	0.016	0.283
Constant	0.609	2.608	0.815