Intra-abdominal pressure and residual renal function decline in peritoneal dialysis: a threshold-based investigation

Figures & data

Figure 1. Flow diagram of study inclusion.

Table 2. Changes in residual renal function in patients with newly initiated PD.

Variables		H/t/z	p Value
Residual eGFR (mL/min/1.73 m^2)
Month 0	5.20 ± 2.00	37.445	< 0.001
Month 6	3.41 ± 2.18
Month 12	2.75 ± 2.41
24-h urine volume (mL)
Month 6	1117.42 ± 609.79	−2.113	0.035
Month 12	894.19 ± 591.07
24-h ultrafiltration volume (mL)
Month 6	601.77 ± 468.54	−1.121	0.262
Month 12	709.97 ± 600.33
IAP (cmH2O)
Month 6	16.13 ± 3.06	−2.121	0.036
Month 12	15.04 ± 2.93

Table 1. Comparison of baseline characteristics and residual renal function between high-IAP and nonhigh-IAP groups.

Variables	Total (n = 62)	Nonhigh IAP group (n = 39)	High-IAP group (n = 23)	t/z/χ^2	p Value
Age (year)	50.53 ± 13.29	50.10 ± 12.60	51.26 ± 14.64	−0.329	0.743
Gender, n (% female)	39(62.9)	27(69.2)	12(52.2)	1.804	0.179
BMI (kg/m^2)	23.93 ± 3.74	23.86 ± 3.83	24.03 ± 3.68	−0.168	0.867
BSA (m^2)	1.67 ± 0.19	1.67 ± 0.19	1.67 ± 0.18	−0.122	0.903
Blood pressure (mmHg)
Systolic	145.08 ± 18.22	144.05 ± 20.00	146.83 ± 14.97	−0.576	0.567
Diastolic	88.16 ± 10.70	89.74 ± 10.86	85.48 ± 10.07	−1.534	0.130
HbA1c (%)	5.93 ± 1.20	5.78 ± 1.08	6.06 ± 1.35	−0.488	0.633
Heart race	77.94 ± 8.46	77.08 ± 8.56	79.39 ± 8.26	−1.189	0.234
Cause of ESKD, n (%)
Chronic glomerulonephritis	18(29.0)	12(30.8)	6(26.1)	0.154	0.695
Diabetic nephropathy	17(27.4)	8(20.5)	9(39.1)	2.520	0.112
Hypertensive nephropathy	20(32.3)	14(35.9)	6(26.1)	0.637	0.425
Other causes	7(11.3)	5(12.8)	2(9.0)	0.006	0.936
Major comorbid conditions, n (%)
Diabetes	3(4.8%)	1(2.5%)	2(8.6%)	0.225	0.635
Hypertension	16(25.8)	11(28.2)	5(21.7)	0.316	0.574
Coronary artery disease	9(14.5)	7(17.9)	2(9.0)	0.392	0.531
Cerebrovascular disease	8(12.9)	4(10.3)	4(17.4)	0.174	0.676
Laboratory parameters
Hemoglobin (g/L)	105.73 ± 17.47	105.36 ± 19.27	106.35 ± 14.30	−0.214	0.832
albumin (g/L)	37.80 ± 19.86	35.64 ± 3.97	41.47 ± 32.30	−0.634	0.526
Calcium (mmol/L)	2.22 ± 0.23	2.25 ± 0.26	2.17 ± 0.16	−1.509	0.131
Phosphate (mmol/L)	1.68 ± 0.41	1.72 ± 0.46	1.60 ± 0.31	−0.649	0.517
eGFR at ESKD onset (mL/min/1.73 m^2)	5.20 ± 2.00	4.72 ± 1.94	6.01 ± 1.88	−2.566	0.013
D/P4	0.66 ± 0.13	0.67 ± 0.13	0.65 ± 0.13	0.495	0.623
IAP (cmH2O)	15.53 ± 2.86	13.70 ± 1.17	18.64 ± 2.07	−10.486	<0.001
ΔUrine volume (mL)	225.32 ± 480.12	75.90 ± 314.83	478.70 ± 601.04	−3.121	0.002
ΔUltrafiltration volume (mL)	−98.68 ± 598.64	−70.72 ± 630.77	−146.09 ± 550.18	0.476	0.636
ΔResidual renal eGFR (mL/min/1.73 m^2)	0.66 ± 1.25	0.24 ± 0.68	1.36 ± 1.64	−3.694	<0.001
ΔResidual renal eGFR (mL/min/1.73 m^2/month)	0.11 ± 0.21	0.40 ± 0.11	0.23 ± 0.27	−3.694	<0.001

BMI: body mass index; BSA: body surface area; ESKD: end-stage kidney disease; eGFR: estimated glomerular filtration rate; D/P4: dialysate-to-plasma concentration ratio of creatinine at 4 h; IAP: intra-abdominal pressure

Δresidual renal eGFR, Δurinary volume, Δultrafiltration volume are all variables at 6 months – variables at 12 months; Δresidual renal eGFR (month) = (6-month residual kidney eGFR – 12-month residual renal eGFR)/6

Table 3. Independent risk factors associated with rapid decline of residual.

Variables	Univariate analysis			Multivariate analysis
	Unadjusted OR	95% CI	p Value	Adjusted OR	95% CI	p Value
Age (years)	1.016	0.977–1.057	0.424	–	–	–
Female (versus male)	0.682	0.241–1.933	0.471	–	–	–
Body mass index (kg/m^2)	1.067	0.929–1.224	0.360	–	–	–
eGFR at ESKD onset (mL/min/1.73 m^2)	1.214	0.934–1.577	0.148	–	–	–
IAP (cmH20)	1.787	1.320–2.419	<0.001	1.679	1.187–2.374	0.003
Major comorbid factors				–	–	–
Diabetes mellitus (versus no)	5.314	1.570–17.988	0.007	5.275	1.028–27.066	0.046
Hypertension (versus no)	1.524	0.551–4.212	0.417	–	–	–
Treatment parameters				–	–	–
Diuretics (versus no)	2.644	0.930–7.518	0.068	–	–	–
RASi (versus no)	0.282	0.091–0.871	0.028	0.442	0.099–1.960	0.282
Proteinuria (versus no)	4.167	1.352–12.828	0.013	4.853	1.051–22.412	0.043
D/P4	3.727	0.069–200.849	0.518	–	–	–
PD prescription		–	–	–	–	–
1.5%*2*4 h	1.000	–	–	–	–	–
1.5%*3*4 h	1.257	0.249–6.357	0.782	–	–	–
1.5%*4*4 h	1.179	0.369–3.760	0.781	–	–	–

Figure 2. Correlation of IAP with the RRF. IAP: intra-abdominal pressure; RRF: residual renal function.

Figure 3. ROC curves for the IAP-predicted RRF decline. IAP: intra-abdominal pressure; RRF: residual renal function; ROC: receiver operating characteristic.

Figure 4. Validation threshold of 15.65 cmH₂O.