ACP5 and chronic kidney disease: We found no interaction between time and group in any of the bone markers and thus no evidence that CKD affects their circadian rhythm compared to healthy controls (CTX (p = 0.154), P1NP (p = 0.340), osteocalcin (p = 0.132), BAP (p = 0.382) and TRAcP (p = 0.218)) (Fig. 1A–E).