Reframing incremental peritoneal dialysis: prioritizing minimum glucose exposure to preserve residual kidney function

To the Editor,

Residual kidney function (RKF) is a major contributor to survival in patients undergoing peritoneal dialysis (PD). Therefore, any PD approach that aims to optimize outcomes must place the protection of RKF at its core.

Repeated and cumulative exposure of the peritoneal membrane to glucose-based dialysis solutions is a primary driver of peritoneal membrane injury and progressive ultrafiltration loss [1]. In addition, glucose exposure also contributes to accelerated decline in RKF. Thus, peritoneal membrane integrity and RKF preservation are interconnected therapeutic priorities, both directly influenced by glucose burden.

While international guidelines from the International Society for Peritoneal Dialysis acknowledge incremental PD as a rational and patient-centered approach, they currently provide no quantitative or mechanistic definition based on measurable parameters such as glucose exposure, solute clearance, or preservation of RKF [2]. Also, the incremental PD term has been inconsistently defined across the literature. Some studies have described incremental PD as a reduction in the number of daily exchanges, variation in fill volumes, or as flexible treatment schedules. Although these approaches generally share the goal of personalizing PD intensity, they do not guarantee the most biologically meaningful target, namely, reduction of cumulative glucose exposure that would protect the RKF and peritoneal membrane.

On the other hand, the kinetic modeling work by Guest et al. demonstrated, using a modified three-pore model across all peritoneal transport types, that adequacy targets (weekly K_t/V ≥ 1.7) can be achieved in incident PD patients with residual glomerular filtration rate (GFR) values as low as 4–6 ml/min/1.73 m² using only one to three low-tonicity (1.36%) glucose or icodextrin exchanges per day [3]. These regimens not only met clearance goals but also minimized carbohydrate absorption, highlighting that dialysis adequacy and low glucose exposure are not mutually exclusive. Complementary review literature on incremental PD emphases that the biological aim of incremental PD is not just achieving operational metrics but preserving RKF and reducing cumulative metabolic and peritoneal stress as part of a strategy of aligning solute and volume control with membrane and RKF protection [4]. Beyond reducing the dialysate refill volume or dwell time, peritoneal rest also contribute favorable effect on peritoneal membrane recovery by reducing ongoing injurious exposure. This effect has documented in the rat studies and clinical and translational reports [5].

Our center has applied the proposed glucose-minimizing incremental PD strategy in a cohort of 28 incident PD patients. The median follow-up durations were 39 months (range 30–50) for the continuous ambulatory PD(CAPD) group and 27 months (range 10–74) for the automated PD[automated peritoneal dialysis (APD)] group (Table 1). Whereas all CAPD patients retained measurable RKF, 21 out of 23 APD patients (91%) maintained RKF during the observation period.

Table 1:

Patient cohorts managed using glucose-minimizing incremental PD.

Parameter	CAPD Group	APD Group
Number of patients (n)	5	23
Follow-up duration, months, median (min–max)	39 (30–50)	27 (10–74)
Weekly schedule	4–5 days/week	4–5 nights/week
Exchange pattern	3 exchanges/day, 4 hours waiting time	4 nightly cycles, 8 hours
Fill volume, ml	1500	1500
RKF outcome	All still have RKF	21 patients (91%) have RKF
	1 patient died with RKF due to hemorrhagic CVE	2 patients lost RKF due to recurrent peritonitis at months 12 and 18
Urine volume ml/day	880 (750–1250)	1770 (500–2000)
Mean (min–max)
K t/V (week) mean (min–max)	2.1 (1.8–2.4)	2.3 (1.9–3.2)

CVE, cerebro-vascular event.

In this context, incremental PD could be defined as a PD prescription that achieves International Society for Peritoneal Dialysis adequacy targets with the minimum feasible cumulative dialysate glucose exposure, determined by the patient’s RKF, peritoneal transport characteristics, and clinical status.

Key components of incremental PD include as follows; (i) patients with incremental PD should possess a clinically meaningful level of RKF, for example, a urine output exceeding 500 ml/day or an estimated GFR of ∼3–4 ml/min/1.73 m²; (ii) administering PD 4–5 days per week, with rest days preferably not consecutive, thereby providing both membrane protection and increased patient flexibility, which may enhance PD adherence; (iii) lower-glucose concentration dialysates are favored whenever feasible, particularly at minimal volumes, to reduce cumulative glucose exposure; (iv) unnecessary escalation of therapy is avoided as long as RKF remains stable and clinical parameters do not deteriorate; (v) patient management relies on regular monitoring of urine output, volume status, overall well-being, and K_t/V to guide therapy adjustments [2]; (vi) APD could be preferred, as it can reduce patient burden and extend intra-abdominal dry periods; (vii) all patients should use intensive diuretic treatment as they need; and (viii) all patients should use maximum tolerated dosage of angiotensin converting enzyme inhibitor or angiotensinogen receptor blocker to preserve RKF.

CONFLICT OF INTEREST STATEMENT

None declared.