Change in 24-hour urine phosphate-to-creatinine ratio over 12 months in response to nicotinamide and lanthanum carbonate in nondialysis CKD. Changes in 24-hour urine phosphate-to-creatinine ratio in milligrams per gram by treatment arm in the COMBINE trial, presented as means with error bars reflecting ±1 SD. N-L, nicotinamide active/lanthanum carbonate active; N-p, nicotinamide active/lanthanum carbonate placebo; p-L, nicotinamide placebo/lanthanum carbonate active; p-p, nicotinamide placebo/lanthanum carbonate placebo.