The appropriateness of finerenone initiation, dosing, and outcomes in diabetic kidney disease: data from real world practice

Abstract

Background

Finerenone has been shown to improve renal outcomes in patients with diabetic kidney disease. Appropriate use according to the Kidney Disease: Improving Global Outcomes (KDIGO) guideline criteria are essential to maximize its clinical benefit. However, the initiation and monitoring requirements are complex, making full adherence challenging in real-world practice, especially in resource-limited settings.

Methods

This retrospective study was conducted at Somdech Phra Pinklao Hospital, Bangkok, Thailand, and included all adult patients who received finerenone between March 2023 and September 2025. The primary outcome was the proportion of patients who fulfilled guideline-based indications and were prescribed the appropriate starting dose of finerenone according to KDIGO recommendations.

Results

A total of 57 patients were included (mean age 70.3 ± 12.9 years). Only 24 (42.1%) fulfilled all KDIGO-based criteria for finerenone initiation and were prescribed the appropriate starting dose. The criterion least frequently fulfilled was the use of a maximally tolerated renin–angiotensin system inhibitor (RASi), achieved in only 32 patients (56.1%). In the subgroup analysis, the annual rate of estimated glomerular filtration rate (eGFR; mL/min/1.73 m²) decline was comparable between the guideline-adherent and non-adherent groups (-6.69 ± 15.32 vs. -5.54 ± 8.41; p = 0.762), and the proportion of patients with albuminuria/proteinuria improvement was also similar (20.8% vs. 42.4%; p = 0.088).

Conclusions

A significant proportion of finerenone prescriptions did not adhere to guideline recommendations. These findings highlight the need to strengthen adherence to guideline-based prescribing and monitoring. While our results suggest that finerenone maintains renal efficacy and safety in clinical practice despite suboptimal guideline adherence, further larger clinical studies are warranted to confirm these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-026-04882-5.

Introduction

Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease globally [1–3]. Non-steroidal mineralocorticoid receptor antagonists (nsMRAs) have been shown to improve composite kidney outcomes in multiple clinical trials and are considered a new therapeutic pillar in the treatment of DKD [4–6]. However, their availability and cost present a challenge for routine use in resource-limited settings. In such environments, it is essential to ensure that the use of high-cost medications like finerenone aligns with guideline-based indications to maximize clinical benefit [7].

According to the 2024 Kidney Disease: Improving Global Outcomes (KDIGO) CKD guidelines, nsMRAs are recommended for patients with DKD who meet al.l of the following criteria: adults with type 2 diabetes, an eGFR ≥ 25 mL/min/1.73 m², a normal serum potassium concentration, and persistent albuminuria (urine albumin-to-creatinine ratio > 30 mg/g) despite receiving the maximum tolerated dose of a renin–angiotensin system inhibitor (RASi) [8, 9]. In addition, serum potassium should be monitored one month after initiating therapy and subsequently every four months.

Given the relatively complex initiation and monitoring requirements, the appropriate use of finerenone in real-world clinical practice can be challenging and may lead to deviations from guideline-recommended prescribing practices. As a result, its effectiveness and safety in routine care may differ from the outcomes reported in large randomized controlled trials [10]. To the best of the authors’ knowledge, no real-world studies on finerenone have been conducted in resource-limited settings since its introduction. This study aims to evaluate the appropriateness of finerenone use and to assess its clinical effectiveness and safety in a real-world setting.

Materials and methods

Study design and patients

This retrospective, non-interventional study was conducted at Somdech Phra Pinklao Hospital and included all adult patients aged over 18 years who received finerenone between March 2023 and September 2025. Patients who obtained the medication on behalf of another person were excluded from the study. This study was approved by the Research Ethics Committee, Royal Thai Navy Medical Department, in accordance with the Declaration of Helsinki and ICH-GCP guidelines (Certificate of Approval No. RP014/68). Given the retrospective design, the requirement for informed consent was waived, and all analyses were performed using de-identified data.

Data collection

Baseline patient characteristics including age, sex, body mass index (BMI), comorbidities, current medications, and blood pressure were retrospectively extracted at the time of finerenone initiation. Relevant laboratory parameters such as serum creatinine, eGFR, urine microalbumin, and serum potassium were collected throughout the study period until September 17, 2025. Any missing laboratory parameters were reported as missing data, and the specific sample size (n) for each missing variable is indicated in the respective results tables. In addition, data on the prescribed dose of finerenone and the use of potassium-binding agents were recorded. The specialty of the prescribing physician, such as nephrologist, cardiologist, or endocrinologist, was also documented. Follow-up time was calculated from the initiation of finerenone until discontinuation of finerenone, loss to follow-up, last available record, or study end, whichever came first.

The primary outcome of this study was the appropriate use of finerenone, defined as meeting both the correct indication and the appropriate starting dose according to KDIGO guidelines (details provided in the Definitions section) [8]. Secondary outcomes included the improvement in albuminuria, the annual rate of eGFR decline, the incidence of finerenone-related complications (including hyperkalemia, symptomatic hypotension, and acute kidney injury [AKI]), the discontinuation rate of finerenone, and the corresponding reasons for drug discontinuation. Additionally, the appropriateness of finerenone dose adjustment was evaluated 1 month after initiation.

Definitions

Appropriate indication for finerenone initiation was defined as fulfillment of all of the following criteria at baseline: (1) a diagnosis of CKD and type 2 diabetes mellitus (T2DM); (2) an eGFR of ≥ 25 mL/min/1.73 m²; (3) the presence of albuminuria, defined as a urine albumin-to-creatinine ratio (UACR) ≥ 30 mg/g, a urine dipstick result of at least trace, or a urine protein-to-creatinine ratio (UPCR) > 150 mg/g; (4) concurrent use of the maximum tolerated dose of either an angiotensin-converting enzyme inhibitor (ACEi) or an angiotensin receptor blocker (ARB); and (5) a serum potassium level < 5.0 mmol/L. These criteria were adapted from the 2024 KDIGO CKD guidelines [8]. The cutoff value for serum potassium was based on the U.S. Food and Drug Administration (FDA) prescribing recommendations for initiating finerenone [8, 9]. The correct starting dose of finerenone was defined as 20 mg once daily for patients with an eGFR ≥ 60 mL/min/1.73 m², and 10 mg once daily for those with an eGFR between 25 and 59 mL/min/1.73 m², in accordance with KDIGO clinical guidelines.

Maximum tolerated dose of ACEi or ARB was defined as the highest dose that could be maintained without adverse effects such as hypotension, hyperkalemia, or worsening renal function. In cases where explicit documentation of RASi intolerance was absent, we reviewed objective clinical markers to determine the maximally tolerated dose. This included a history of hyperkalemia, hypotension, or AKI associated with previous titration attempts. If these clinical indicators were present, the patient was considered to be on their maximally tolerated dose. Conversely, if no such documentation or objective clinical evidence of intolerance was available, the patient was categorized as not being on a maximally tolerated dose, in accordance with KDIGO criteria.

Hyperkalemia was defined as a serum potassium level ≥ 5.0 mmol/L, and severe hyperkalemia was defined as a serum potassium level > 6.0 mmol/L [6]. AKI was defined as an increase in serum creatinine of ≥ 0.3 mg/dL from baseline within 48 h or an increase to ≥ 1.5 times the baseline value within 7 days [11]. Appropriate finerenone dose adjustment at one month was defined according to the KDIGO recommendations as follows: up-titration from 10 mg to 20 mg in patients with serum potassium ≤ 4.8 mmol/L at one month, maintaining the same dose (10 mg or 20 mg) if serum potassium was 4.9–5.5 mmol/L, and withholding treatment if serum potassium exceeded 5.5 mmol/L [9]. Improvement of albuminuria was defined as a ≥ 30% reduction in UACR from baseline to the last available visit. Improvement of proteinuria was defined as a ≥ 30% reduction in UPCR from baseline to the last available visit. Improvement of urine dipstick was defined as at least one grade improvement on dipstick testing [12].

Statistical analyses

All patients who received finerenone at the study site within the specified study period were included in the analysis. Descriptive statistics were presented as the mean ± standard deviation for normally distributed variables, median (interquartile range) for non-normally distributed variables, and frequency (percentage) for categorical variables. Continuous variables between groups were compared using the Student’s t-test or the Mann–Whitney U test, while categorical variables were compared using the Chi-square or Fisher’s exact test, as appropriate. Within-group comparisons of laboratory parameters between baseline and the last follow-up visit were performed using the paired t-test or Wilcoxon signed-rank test. A two-tailed p-value < 0.05 was considered statistically significant for all analyses. All statistical analyses were conducted using IBM SPSS Statistics version 18.0 (SPSS Inc., Chicago, IL, USA).

The estimated glomerular filtration rate (eGFR) was calculated using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) 2021 equation. A linear mixed-effects model (LMM) for repeated measures, using restricted maximum likelihood (REML) estimation and an autoregressive (AR) covariance structure, was employed to analyze the rate of eGFR decline (eGFR slope). The fixed effects included the guideline-adherence status (adherent vs. non-adherent), the duration of follow-up (time), and their interaction (group-by-time interaction). The random effects included a random intercept and a random slope for each participant to account for individual variability in eGFR changes over time.

Albuminuria/proteinuria improvement by any criterion (hierarchical definition) in Table 3 was assessed using a pre-specified hierarchical algorithm. UACR was used as the preferred biomarker; if UACR data were unavailable at baseline, UPCR was used instead; and if both were unavailable, urine dipstick results were used. Each participant was assigned to only one analysis set according to baseline data availability (UACR → otherwise UPCR → otherwise dipstick) to prevent double counting across rows.

Table 3.

Efficacy and safety outcomes of finerenone treatment (N = 57)

Variable	Value
eGFR decline per year (mL/min/1.73 m²), mean ± SD	-6.00 ± 11.50 (n = 40) *
Improvement of proteinuria/albuminuria, n (%)
-Improve UACR by ≥ 30% from baseline	6 (25.0%) (n = 24) †
-Improve UPCR by ≥ 30% from baseline	8 (29.6%) (n = 27) ‡
-Improve urine dipstick by ≥ 1 level from baseline	18 (36.7%) (n = 49) §
-Albuminuria/proteinuria improvement by any criterion (hierarchical definition)	19 (33.3%) (n = 57) ¶
Follow up time (months), median (p25-p75)	9.0 (3.0–12.0)
Discontinuation of finerenone, n (%)	12 (21.1%)
Reasons for discontinuation, n (%)
-Hyperkalemia	2 (3.5%)
-AKI	3 (5.2%)
-Hypotension	1 (1.8%)
-Non-adherence to medication	2 (3.5%)
-Loss to follow up	4 (7.0%)
Use of potassium exchange resin, n (%)
-Initiated concurrently with finerenone	2 (3.5%)
-Already receiving resin at baseline	7 (12.3%)

Abbreviations: eGFR, estimated glomerular filtration rate; UACR, urine albumin-to-creatinine ratio; UPCR, urine protein-to-creatinine ratio; SD, standard deviation; p25–p75, 25th–75th percentile; AKI, acute kidney injury

* The annual rate of eGFR decline was calculated for participants with follow-up durations of at least 6 months, with a total of 40 out of 57 included

† Denominator includes 24 participants with available baseline UACR data

‡ Denominator includes 27 participants with available baseline UPCR data

§ Denominator includes 49 participants with available baseline urine dipstick results

¶ Denominator includes 57 participants. Improvement by any criterion (hierarchical definition) was determined as follows: the urine albumin-to-creatinine ratio (UACR) was used when available; if UACR data were unavailable, the urine protein-to-creatinine ratio (UPCR) was used; and if both were unavailable, urine dipstick results were applied. Each participant contributed a single outcome

Results

A total of 57 patients were included in this study. Baseline characteristics are summarized in Table 1. Patients were elderly on average, with mean age of 70.3 ± 12.9 years, and the majority were male (37 [65.0%]). Nearly all patients had type 2 diabetes mellitus (55 [96.5%]). All patients had at least one comorbid condition. Hypertension, dyslipidemia, coronary artery disease, and cerebrovascular disease were present in 57 (100%), 54 (94.7%), 7 (12.3%), and 8 (14%) patients, respectively. Only one patient (1.8%) had congestive heart failure, and two patients (3.5%) had atrial fibrillation.

Table 1.

Baseline characteristics (N = 57)

Variable	Value
Age (years), mean ± SD	70.3 ± 12.9
Sex, n (%)
-Male	37 (65.0%)
-Female	20 (35%)
Mean body mass index (kg/m²)	24.9 ± 4.5
Underlying condition, n (%)
-Diabetes mellitus	55 (96.5%)
-Hypertension	57 (100%)
-Dyslipidemia	54 (94.7%)
-Coronary artery disease	7 (12.3%)
-Cerebrovascular disease	8 (14%)
-Congestive heart failure	1 (1.8%)
-Atrial fibrillation	2 (3.5%)
SBP (mmHg), mean ± SD	140.6 ± 20
DBP (mmHg), mean ± SD	73.1 ± 12.7
Serum creatinine (mg/dL), mean ± SD	1.6 ± 0.4
eGFR (mL/min/1.73 m²), mean ± SD	44.86 ± 18.68
eGFR category, n (%)
15–29 mL/min/1.73 m²	7 (12.3%)
30–44 mL/min/1.73 m²	29 (50.9%)
45–59 mL/min/1.73 m²	13 (22.8%)
≥ 60 mL/min/1.73 m²	8 (14.0%)
UACR (mg/g creatinine), median(p25-p75)	219.5 (44.0-363.8)
UACR category, n (%)
< 30 mg/g creatinine	5 (8.8%)
30–299 mg/g creatinine	12 (21.1%)
≥ 300 mg/g creatinine	7 (12.3%)
Not done	33 (57.9%)
UPCR (mg/g creatinine), median(p25-p75)	1,600 (600-3,200)
UPCR category, n (%)
< 150 mg/g creatinine	0 (0%)
150–499 mg/g creatinine	4 (7.0%)
> 500 mg/g creatinine	23 (40.4%)
Not done	30 (52.6%)
Urine albumin dipstick, n (%)
Negative	7 (12.3%)
Trace	4 (7.0%)
1+	14 (24.6%)
2+	16 (28.1%)
3+	7 (12.3%)
4+	1 (1.8%)
Not done	8 (14.0%)
Serum potassium (mmol/L), mean ± SD	4.2 ± 0.4
Hemoglobin (g/dL), mean ± SD (n = 53)	12.8 ± 2.1
HbA1c, n (%)
≥ 9.0%	1 (1.8%)
7.0%-8.9%	21 (36.8%)
< 7.0%	33 (57.9%)
Not done	2 (3.5%)
LDL-c (mg/dL), mean ± SD (n = 52)	80.8 ± 24.9
Baseline Medication, n (%)
ACEi/ARB	49 (86%)
SGLT2i	50 (87.7%)
GLP-1 RA	11 (19.3%)
Insulin	8 (14%)
Diuretic	7 (12.3%)

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; UACR, urine albumin-to-creatinine ratio; UPCR, urine protein-to-creatinine ratio; HbA1c, glycated hemoglobin; LDL-c, low-density lipoprotein cholesterol; ACEi, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; SGLT2i, sodium-glucose cotransporter-2 inhibitor; GLP-1 RA, glucagon-like peptide-1 receptor agonist

The mean baseline serum creatinine level was 1.6 ± 0.4 mg/dL, and the majority of patients (29 [50.9%]) had CKD stage 3b (eGFR 30–44 mL/min/1.73 m²). The median UACR and UPCR were 219.5 mg/g creatinine (interquartile range [IQR], 44.0–363.8) and 1,600 mg/g creatinine (IQR, 600–3,200), respectively. Data on UACR and UPCR were unavailable for a considerable proportion of patients (33 [57.9%] for UACR and 30 [52.6%] for UPCR). The mean serum potassium was 4.2 ± 0.4 mmol/L. Approximately 86% of patients were receiving ACEi or ARB therapy, the majority of whom were taking losartan (24 [42.1%]). Details of baseline medications are summarized in Supplementary Table S1.

Table 2 shows the characteristics of finerenone prescription. Only 32 patients (56.1%) met the guideline-based criteria for finerenone initiation. The vast majority of patients (52 [91.2%]) had albuminuria or proteinuria, as determined by UACR, UPCR, or urine dipstick results. Most patients had an eGFR ≥ 25 mL/min/1.73 m² (55 [96.5%]) and a serum potassium < 5.0 mmol/L (56 [98.2%]) at the time of initiation, consistent with the guideline recommendations. The criterion most frequently not fulfilled was the use of a maximum tolerated dose of ACEi/ARB, which was achieved in only 32 patients (56.1%). The correct initial dose of finerenone was prescribed in 48 patients (84.2%). Physicians prescribed an initial dose of 10 mg per day in 94.7% of patients. At 1 month, appropriate dose adjustment was achieved in 14 patients (24.6%), whereas 13 patients (22.8%) underwent inappropriate titration. Potassium data were unavailable for 24 patients (42.1%) at one month, and 6 patients (10.5%) had not yet completed 1 month of follow-up; therefore, the appropriateness of dose adjustment could not be evaluated in these patients.

Table 2.

Evaluation of finerenone prescribing appropriateness, including initiation criteria, dosing, and prescribing specialties (N = 57)

Variable	Value
Guideline-based initiation criteria for finerenone†, n (%)
-Diagnosis of diabetes mellitus	55 (96.5%)
-Presence of albuminuria or proteinuria	52 (91.2%)
-eGFR ≥ 25 mL/min/1.73 m² at initiation	55 (96.5%)
-Receiving maximum tolerated ACEi/ARB dose	32 (56.1%)
-Serum potassium < 5.0 mmol/L at initiation	56 (98.2%)
-Meet all guideline-based initiation criteria	32 (56.1%)
Correct starting dose of finerenone‡, n (%)	48 (84.2%)
Meeting all guideline-based initiation criteria and receiving the correct starting dose of finerenone, n (%)	24 (42.1%)
Starting dose, n (%)
-10 mg/day	54 (94.7%)
-20 mg/day	3 (5.3%)
Appropriate finerenone dose adjustment at one month§, n (%)
-Appropriate	14 (24.6%)
-Inappropriate	13 (22.8%)
- Unable to evaluate due to missing serum potassium data at one month, n (%)	24 (42.1%)
- Unable to evaluate due to follow-up period shorter than 1 month, n (%)	6 (10.5%)
Specialties prescribing finerenone, n (%)
-Nephrologist	48 (84.2%)
-Cardiologist	7 (12.3%)
-Endocrinologist	2 (3.5%)

Abbreviations: eGFR, estimated glomerular filtration rate; ACEi, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; DM, diabetes mellitus; K, serum potassium

†The guideline-based criteria for finerenone initiation comprised five components: (1) a confirmed diagnosis of chronic kidney disease (CKD) with type 2 diabetes mellitus (T2DM); (2) an estimated glomerular filtration rate (eGFR) ≥ 25 mL/min/1.73 m²; (3) evidence of albuminuria, defined as a urine albumin-to-creatinine ratio (UACR) ≥ 30 mg/g, a urine dipstick result of ≥ trace, or a urine protein-to-creatinine ratio (UPCR) > 150 mg/g; (4) concomitant use of the maximally tolerated dose of an angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB); and (5) a baseline serum potassium level < 5.0 mmol/L, in accordance with the KDIGO clinical practice guidelines. (Kidney Int. 2024;105[S1]: S117–S314)

‡The correct starting dose of finerenone was defined as 20 mg once daily for patients with an eGFR ≥ 60 mL/min/1.73 m² and 10 mg once daily for those with an eGFR between 25 and 59 mL/min/1.73 m², in accordance with the KDIGO clinical practice guidelines. (Kidney Int. 2024;105[S1]: S117–S314)

§Appropriate finerenone dose adjustment at one month was defined based on KDIGO recommendations as follows: up-titration from 10 mg to 20 mg once daily in patients with serum potassium ≤ 4.8 mmol/L; maintaining the current dose (10 mg or 20 mg) if serum potassium was between 4.9 and 5.5 mmol/L; and temporarily withholding finerenone if serum potassium exceeded 5.5 mmol/L. (Kidney Int. 2024;105[S1]: S117–S314)

Clinical outcomes and complications associated with finerenone use are summarized in Table 3. The annual rate of eGFR decline was calculated in patients with at least 6 months of follow-up (n = 40) and was − 6.00 ± 11.50 mL/min/1.73 m². A ≥ 30% reduction from baseline in UACR and UPCR was achieved in 6 of 24 patients (25.0%) and 8 of 27 patients (29.6%), respectively. An improvement of at least one level in urine albumin dipstick results was observed in 18 of 49 patients (36.7%). Overall, albuminuria/proteinuria improvement by any criterion was achieved in 19 of 57 patients (33.3%). The hierarchical approach used to determine this outcome is described in the Statistical Analysis section. The median follow-up duration was 9.0 (IQR, 3–12) months. Finerenone was discontinued in 12 patients (21.1%). Reasons for discontinuation included hyperkalemia in 2 (3.5%), acute kidney injury in 3 (5.2%), hypotension in 1 (1.8%), non-adherence to medication in 2 (3.5%), and loss to follow-up in 4 (7.0%).

We performed a subgroup analysis comparing patients who met all guideline-based initiation criteria and received the correct starting dose of finerenone (Group A) with those who did not (Group B). Baseline characteristics of the two groups are presented in Supplementary Table S2. Both groups were comparable in demographic and clinical variables, including sex, age, comorbidities, baseline kidney function, concomitant medication use, and albuminuria/proteinuria levels. Efficacy and safety outcomes are summarized in Table 4. The annual rate of eGFR decline was comparable between groups (-6.69 ± 15.32 vs. -5.54 ± 8.41 mL/min/1.73 m²; p = 0.762). Interestingly, a greater proportion of patients in Group B showed improvement in albuminuria/proteinuria (42.4%) compared with Group A (20.8%), although this difference did not reach statistical significance (p = 0.088). The rates of treatment discontinuation and adverse events were similar between groups.

Table 4.

Comparison of efficacy and safety outcomes between participants who met all guideline-based initiation criteria (Group A) and received the appropriate starting dose of finerenone and those who did not (Group B)

Variable	Group A: Fulfilled all guideline-recommended initiation criteria and received the appropriate starting dose (n = 24)	Group B: Did not fulfill all guideline-recommended initiation criteria or did not receive the correct starting dose of finerenone (n = 33)	p-value
eGFR decline per year (mL/min/1.73 m²), mean ± SD	-6.69 ± 15.32 (n = 16) *	-5.54 ± 8.41 (n = 24) *	0.762
Improvement of proteinuria/albuminuria, n (%)
-Improve UACR by ≥ 30% from baseline	1 (9.1%) (n = 11) †	5 (38.5%) (n = 13) †	0.166
-Improve UPCR by ≥ 30% from baseline	3 (23.1%) (n = 13) ‡	5 (35.7%) (n = 14) ‡	0.678
-Improve urine dipstick by ≥ 1 level from baseline	5 (25.0%) (n = 20) §	13 (44.8%) (n = 29) §	0.236
-Albuminuria/proteinuria improvement by any criterion (hierarchical definition)	5 (20.8%) ¶	14 (42.4%) ¶	0.088
Follow up time (months), median (p25-p75)	6.0 (3.0–11.0)	9.0 (3.0–12.0)	0.438
Discontinuation of finerenone, n (%)	8 (33.3%)	4 (12.1%)	0.052
Reasons for discontinuation, n (%)
-Hyperkalemia	2 (8.3%)	0 (0.0%)
-AKI	2 (8.3%)	1 (3.0%)
-Hypotension	1 (4.2%)	0 (0.0%)
-Non-adherence to medication	0 (0.0%)	2 (6.1%)
-Loss to follow up	3 (12.5%)	1 (3.0%)
Use of potassium exchange resin, n (%)
-Initiated concurrently with finerenone	1 (4.2%)	1 (3.0%)	1.000
-Already receiving resin at baseline	5 (20.8%)	2 (6.1%)	0.119

Abbreviations: eGFR, estimated glomerular filtration rate; UACR, urine albumin-to-creatinine ratio; UPCR, urine protein-to-creatinine ratio; SD, standard deviation; p25–p75, 25th–75th percentile; AKI, acute kidney injury

*The annual rate of eGFR decline was calculated for participants with follow-up durations of at least 6 months, including 16 of 24 in Group A and 24 of 33 in Group B

† Denominator includes 11 participants in Group A and 13 participants in Group B with available baseline UACR data

‡ Denominator includes 13 participants in Group A and 14 participants in Group B with available baseline UPCR data

§ Denominator includes 20 participants in Group A and 29 participants in Group B with available baseline urine dipstick results

¶ Denominator includes 24 participants in Group A and 33 participants in Group B. Improvement by any criterion (hierarchical definition) was determined as follows: the urine albumin-to-creatinine ratio (UACR) was used when available; if UACR data were unavailable, the urine protein-to-creatinine ratio (UPCR) was used; and if both were unavailable, urine dipstick results were applied. Each participant contributed a single outcome

Discussion

This retrospective real-world study examined the prescribing patterns and appropriateness of finerenone use. Despite its proven benefits, the expense and limited access to finerenone make routine use challenging in settings with constrained resources. Therefore, careful adherence to guideline-recommended indications is essential to ensure the greatest clinical impact [7]. Most of our patients were elderly with multiple comorbidities and demonstrated albuminuria or proteinuria, representing a population at high risk for renal and cardiovascular complications [13]. Notably, approximately 60% of patients did not undergo baseline UACR measurement; instead, UPCR or urine dipstick results were used as surrogates for albuminuria (Table 1). These real-world findings highlight that a substantial proportion of physicians, particularly in resource-limited settings, rely on alternatives to UACR for assessing albuminuria. This practice, which deviates from KDIGO recommendations, may contribute to the under-detection of albuminuria [14, 15].

In this study, nearly half of the physicians prescribed finerenone to patients who did not fulfill the guideline-recommended criteria for initiation (Table 2). The most frequently satisfied criteria were the presence of type 2 diabetes mellitus (96.5%), eGFR ≥ 25 mL/min/1.73 m² at initiation (96.5%), and serum potassium < 5.0 mmol/L at initiation (98.2%) (Table 2). By contrast, the criterion most often not achieved was the use of a maximum tolerated dose of ACEi/ARB, met in only 56.1% of patients. This observation is consistent with previous data indicating that merely 25–45% of patients attain target dosing [16]. Physicians may be reluctant to up-titrate ACEi/ARB therapy owing to concerns about hyperkalemia or worsening kidney function, particularly when used in combination with nsMRAs [17]. Nevertheless, achieving the maximum tolerated dose has been demonstrated to confer greater cardiovascular and renal benefits [18, 19]. However, the proportion of patients receiving SGLT2 inhibitors in our cohort was substantially higher (87.7% vs. 46.6% in FINE-REAL), likely reflecting the government reimbursement policy in Thailand that ensures full patient access to these agents [10, 20]. Although the majority of our population was already receiving SGLT2 inhibitors, persistent albuminuria/proteinuria remained evident. This underscores a significant residual risk and a high potential for renal progression in these patients. This finding is particularly encouraging, especially as the recent CONFIDENCE trial demonstrated synergistic renal benefits with the combined use of empagliflozin and finerenone [21].

Approximately 22% of physicians did not titrate the finerenone dose appropriately, and 42.1% did not monitor serum potassium at one month as recommended by the KDIGO guidelines. The requirement for early potassium monitoring following finerenone initiation may be challenging in real-world practice, as patients are often accustomed to routine follow-up every 3–4 months. Practical barriers, especially in resource-limited countries such as Thailand, including transportation difficulties and limited caregiver availability, may lead physicians to defer close monitoring [21, 22]. The underlying causes of these practice gaps warrant further exploration in future studies.

In our real-world cohort, 25% of patients achieved a ≥ 30% reduction in UACR after finerenone treatment (Table 3), which is lower than the 53% reported in the FIDELIO-DKD trial [23]. In addition, a mediation analysis combining data from the FIDELIO-DKD and FIGARO-DKD trials reported that more than 50% of participants experienced a ≥ 30% reduction in albuminuria [24]. This discrepancy likely reflects the inherent variability and less standardized treatment conditions observed in real-world clinical practice, particularly in resource-limited settings, where follow-up intervals are often longer and less consistent, and laboratory assessments such as urine microalbumin are frequently performed using UPCR or dipstick testing instead of UACR. Notably, when patients were stratified according to whether they fulfilled all guideline-recommended initiation criteria and received the appropriate starting dose (Group A) versus those who did not (Group B), the clinical outcomes—including albuminuria improvement and rate of eGFR decline—did not differ significantly between the two groups (Table 4). In addition, the incidence of adverse events, such as AKI and hyperkalemia was comparable between groups. These findings suggest that even in less strictly adherent, resource-limited real-world settings, finerenone still confers renal benefits. Consistent with our observations, other real-world studies have also demonstrated that finerenone mitigates eGFR decline and reduces albuminuria [25–29].

About 15% of patients in our cohort were receiving potassium-exchange resins at baseline, and two patients initiated a potassium-exchange resin concurrently with finerenone. This proportion is higher than in the randomized FIDELIO-DKD trial, in which only 2.4% were on a potassium-exchange resin at baseline and 6.5% initiated one during follow-up [30]. Despite the limited cohort size, these findings suggest a clinical trend where vigilant monitoring and the use of potassium binders may enable clinicians to prioritize renal benefits over hyperkalemia concerns in high-risk patients, reflecting a pragmatic approach to finerenone therapy.

In our study, approximately 21% of patients discontinued finerenone (Table 3); among these, only two patients (3.5%) discontinued due to hyperkalemia. This is consistent with the FIDELITY study, which reported a discontinuation rate due to hyperkalemia of about 2.4% [6]. These findings are further supported by real-world studies demonstrating similarly low discontinuation rates related to hyperkalemia [25, 31, 32].

In Thailand, finerenone is categorized as a high-cost medication and is currently excluded from the National List of Essential Medicines (NLEM) [33]. Reimbursement is primarily restricted to the Civil Servant Medical Benefit Scheme (CSMBS)—covering less than 10% of the population—and requires documented non-response to standard NLEM-listed treatments [34]. This administrative process effectively selected a high-risk cohort for our study. Therefore, strict adherence to the KDIGO 2024 guidelines—specifically regarding appropriate initiation criteria (e.g. eGFR ≥ 25 mL/min/1.73 m²) and regular potassium monitoring—is vital to maximize clinical benefits and justify expenditure within this resource-limited context [7].

Strengths of this study include its real-world design, which provides complementary evidence to randomized controlled trials by capturing practical challenges such as loss to follow-up, suboptimal titration, and patient adherence. By identifying that only about half of prescriptions adhered to KDIGO-recommended indications and dosing, this study highlights key practice gaps and provides a foundation for future quality improvement and research initiatives. Furthermore, our study reflects the pragmatic landscape of Thai clinical practice, where proteinuria assessment is not strictly limited to UACR. Crucially, no formal cascade criteria existed at our institution to assign specific tests based on patient severity, thereby mitigating potential selection bias. We comprehensively assessed albuminuria improvement using UACR, UPCR, and dipstick, reflecting diverse monitoring tools in real-world practice. Finally, our findings indicate that patients in Group B, whose treatment did not fully comply with guideline-recommended initiation or dose titration, nevertheless achieved reductions in albuminuria/proteinuria and demonstrated a safety profile similar to that of patients treated according to the guidelines.

Our study has several limitations. First, it was a retrospective, single-center study with a relatively small sample size, which may limit the generalizability of the findings to other populations and healthcare settings. Nevertheless, it provides valuable real-world evidence that can serve as a foundation for future multicenter, prospective investigations. Second, the study was originally designed as a single-arm observational study, and the subsequent post hoc stratification into Groups A and B was exploratory. As a result, the study was not adequately powered to detect statistically significant differences in clinical outcomes between these groups. However, it could serve as a foundation for larger future studies to further validate these findings. Third, the median follow-up duration was 9 months, which may be insufficient to fully capture the long-term renal and cardiovascular effects of finerenone. However, a significant reduction in albuminuria/proteinuria was already observed within this short period, consistent with the early effects reported in pivotal randomized controlled trials. Longer follow-up in larger, multicenter cohorts will be required to confirm the durability and generalizability of these findings. Fourth, a significant proportion of patients had missing potassium monitoring data during follow-up (42.1% at one month). This limitation may have resulted in the underdetection of hyperkalemia, potentially leading to an overestimation of the safety profile. However, it is notable that no episodes of hyperkalemia-associated arrhythmia were documented in the available medical records during the study period. Finally, our analysis estimated the total eGFR slope using all data points from baseline to the last visit; consequently, the results may be influenced by the initial hemodynamic eGFR dip. However, to prioritize the assessment of clinical trajectories over acute effects, we restricted this analysis to patients with a follow-up duration of at least 6 months.

Conclusion

A considerable proportion of finerenone prescriptions deviated from guideline recommendations, predominantly due to suboptimal titration of ACEi/ARB to maximally tolerated doses. These results emphasize the importance of reinforcing guideline-concordant initiation and monitoring strategies. Nevertheless, finerenone demonstrated comparable renal efficacy and safety in patients with partial guideline adherence; further large-scale studies are warranted to confirm these observations.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

PS and SP contributed to the study design. PS contributed to data collection and worked with a statistician on the statistical analysis. PS, SP, TP, and PK contributed to manuscript writing. NS critically reviewed and revised the manuscript. All authors read and approved the final version of the manuscript.

Funding

This study was supported by the Somdech Phra Pinklao Hospital Research Grant.

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethical approval

This study was approved by the Research Ethics Committee, Royal Thai Navy Medical Department, in accordance with the Declaration of Helsinki and ICH-GCP guidelines (Certificate of Approval No. RP014/68).

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.