Symptom scores and clinical measures in benign prostatic hyperplasia

Table 1 Study characteristics, correlation coefficients, and Fisher’s Z Transformation values for all 28 included studies¹

Meta-analysis	Ref.	Country	n	r	Fisher’s Z	SE	95%CI lower (r)	95%CI upper (r)
Meta-analysis 1: IPSS-quality of life (k = 5; n = 705)
IPSS-QoL	Roy et al[18], 2016	India	100	0.693	0.854	0.102	0.575	0.783
	Taneja et al[7], 2017	India	121	0.656	0.786	0.092	0.541	0.747
	Anyimba et al[3], 2023	Nigeria	170	0.760	0.996	0.077	0.688	0.817
	Nketiah et al[6], 2024	Ghana	256	0.541	0.606	0.063	0.448	0.622
	Timilsina et al[23], 2024	Nepal	58	0.910	1.528	0.135	0.852	0.946
Meta-analysis 2: Prostate volume-IPSS (k = 12; n = 1446)
PV-IPSS	Udeh et al[17], 2012	Nigeria	120	-0.004	-0.004	0.092	-0.183	0.176
	Awaisu et al[9], 2021	Nigeria	290	0.179	0.181	0.059	0.065	0.288
	Ngwa-Ebogo et al[24], 2023	Cameroon	45	0.410	0.436	0.154	0.132	0.628
	Hossain et al[25], 2020	Bangladesh	60	0.585	0.670	0.132	0.389	0.730
	Yadav et al[26], 2021	India	154	0.560	0.633	0.081	0.441	0.660
	Rananda et al[4], 2021	Indonesia	86	0.048	0.048	0.110	-0.166	0.257
	Ng et al[2], 2015	India	126	0.400	0.424	0.090	0.242	0.537
	Sadiq et al[27], 2024	Pakistan	45	0.437	0.469	0.154	0.165	0.647
	Maghfira et al[28], 2024	Indonesia	93	0.853	1.267	0.105	0.786	0.900
	Shah et al[11], 2024	Pakistan	158	0.779	1.043	0.080	0.709	0.834
	Almaasah et al[29], 2025	Indonesia	19	0.617	0.720	0.250	0.226	0.837
	Rehman et al[30], 2024	Pakistan	250	0.250	0.255	0.064	0.130	0.363
Meta-analysis 3: IPSS-post-void residual (k = 11; n = 2663)
IPSS-PVR	Ko et al[13], 2010	Korea	309	0.200	0.203	0.057	0.090	0.305
	Cakiroglu[31], 2013	Turkey	152	0.441	0.473	0.082	0.303	0.561
	Aisuodionoe-Shadrach et al[32], 2020	Nigeria	100	0.350	0.365	0.102	0.165	0.511
	Hamza et al[10], 2021	Nigeria	167	0.285	0.293	0.078	0.139	0.419
	Mbouché et al[1], 2022	Cameroon	103	0.000	0.000	0.100	-0.194	0.194
	Anyimba et al[3], 2023	Nigeria	170	0.490	0.536	0.077	0.367	0.597
	Apata et al[5], 2023	Nigeria	150	0.118	0.119	0.082	-0.043	0.273
	Kohler and Kausik[16], 2023	United States	1014	0.151	0.152	0.031	0.090	0.211
	Nketiah et al[6], 2024	Ghana	256	0.085	0.085	0.063	-0.038	0.205
	Shah et al[11], 2024	Pakistan	158	0.599	0.692	0.080	0.489	0.691
	Fazal et al[12], 2025	Pakistan	84	0.920	1.589	0.111	0.879	0.948

¹Anyimba et al[3], Nketiah et al[6], and Shah et al[11] appear in more than one meta-analysis, each reporting separate correlation coefficients for different outcome pairs within the same study.

R: Pearson/Spearman correlation coefficient; Fisher’s Z: Variance-stabilizing transformation computed as 0.5 × ln[(1 + r)/(1 − r)]; SE: Standard error of Fisher’s Z computed as 1/√(N − 3); 95% confidence interval bounds are on the r scale, back-transformed from Fisher’s Z. Negative r values indicate inverse correlations. CI: Confidence interval; IPSS: International Prostate Symptom Score; PV: Prostate volume; PVR: Post-void residual; QoL: Quality of life.

Table 2 Summary of pooled meta-analysis results: Correlation coefficients, Fisher’s Z, and statistical significance for all three outcome pairs¹

Outcome pair	k	Total n	Pooled r	95%CI (r scale)	Fisher’s Z	SE	Z-statistic	P value	Effect size classification
IPSS-quality of life	5	705	0.713	0.557-0.820	0.893	0.135	6.62	< 0.001	Large (Cohen, 1988)
Prostate volume-IPSS	12	1,446	0.457	0.257-0.619	0.493	0.117	4.20	< 0.001	Moderate-to-Large
IPSS-post-void residual	11	2,663	0.363	0.150-0.543	0.380	0.117	3.25	0.001	Moderate

¹Effect size benchmarks per Cohen: Small r = 0.10-0.29; medium r = 0.30-0.49; large r ≥ 0.50. Back-transformation formula: R = (e^2z - 1)/(e^2z + 1).

k: Number of included studies; n: Total participants; Pooled r: Back-transformed Pearson correlation from Restricted Maximum Likelihood random-effects model; 95% confidence interval on r scale obtained by back-transforming Fisher’s Z interval bounds; SE: Standard error of pooled Fisher’s Z; Z-statistic: Wald test of H₀; IPSS: International Prostate Symptom Score; CI: Confidence interval.

Table 3 Heterogeneity statistics for all three random-effects meta-analyses¹

Outcome pair	τ2 (SE)	τ	I2 (%)	H2	Cochran’s Q	df	Q P value
IPSS-quality of life	0.003 (0.064)	0.055	3.26	1.034	4.578	4	0.333
Prostate volume-IPSS	0.062 (0.069)	0.248	38.37	1.623	17.196	11	0.102
IPSS-post-void residual	0.075 (0.067)	0.274	51.18	2.048	20.558	10	0.024

¹I² classification: < 25% low; 25%-50% moderate; 50%-75% substantial; > 75% considerable. Q P < 0.10 indicates significant heterogeneity; Q has limited power with small k.

τ²: Between-study variance estimated by Restricted Maximum Likelihood; τ: √τ² (standard deviation of true effects); I²: Proportion of total variability attributable to between-study heterogeneity; H²: Ratio of total variability to expected sampling variability; Cochran’s Q: χ² heterogeneity test; df: k-1; IPSS: International Prostate Symptom Score; SE: Standard error.

Table 4 Publication bias assessment: Egger’s regression test, Kendall’s Tau (Begg’s Test), and Rosenthal’s Fail-Safe N for all three meta-analyses¹

Outcome pair	Egger’s intercept	Egger’s P value	Kendall’s τ	Kendall’s P value	Fail-Safe n	Overall bias assessment
IPSS-quality of life	1.774	0.076	0.600	0.233	83	No compelling evidence of bias
Prostate volume-IPSS	0.659	0.510	0.107	0.630	118	No evidence of publication bias
IPSS-post-void residual	1.710	0.0872	0.309	0.218	78	No significant bias; borderline Egger’s2

¹Fail-Safe N threshold = 5k + 10; International Prostate Symptom Score-quality of life = 35; Prostate volume-International Prostate Symptom Score = 70; International Prostate Symptom Score-post-void residual = 65. Values exceeding the threshold indicate robustness against publication bias.

²Borderline Egger’s result (P = 0.087) for International Prostate Symptom Score-post-void residual, with k = 11. Kendall’s Tau (Begg’s test): P < 0.05 indicates significant rank correlation between effect size and standard error. Egger’s test: P < 0.05 indicates statistically significant funnel plot asymmetry.

IPSS: International Prostate Symptom Score.

Table 5 Complete leave-one-out sensitivity analysis results for all 28 studies across all three meta-analyses¹

Meta-analysis	Ref.	New Fisher’s Z	New Pooled r	Δr	95%CI	Stability
Meta-analysis 1: IPSS-quality of life (Full model r = 0.713; 95%CI: 0.557-0.820)
	None (Full model)	0.893	0.713	-	0.557-0.820	Reference
	Roy et al[18], 2016	0.837	0.684	-0.029	-	Stable
	Taneja et al[7], 2017	0.850	0.691	-0.022	-	Stable
	Anyimba et al[3], 2023	0.789	0.658	-0.055	-	Stable
	Nketiah et al[6], 2024	0.975	0.751	+0.038	-	Stable
	Timilsina et al[23], 2024	0.780	0.653	-0.060	-	Stable
Meta-analysis 2: Prostate volume-IPSS (Full model r = 0.457; 95%CI: 0.257-0.619)
	None (Full model)	0.493	0.457	-	0.257-0.619	Reference
	Udeh et al[17], 2012	0.487	0.452	-0.005	-	Stable
	Hossain et al[25], 2020	0.437	0.411	-0.046	-	Stable
	Rananda et al[4], 2021	0.449	0.421	-0.036	-	Stable
	Awaisu et al[9], 2021	0.514	0.473	+0.016	-	Stable
	Yadav et al[26], 2021	0.424	0.401	-0.056	-	Stable
	Ng et al[2], 2015	0.449	0.421	-0.036	-	Stable
	Ngwa-Ebogo et al[24], 2023	0.447	0.419	-0.038	-	Stable
	Sadiq et al[27], 2024	0.446	0.419	-0.038	-	Stable
	Rehman et al[30], 2024	0.487	0.452	-0.005	-	Stable
	Maghfira et al[28], 2024	0.391	0.372	-0.085	-	Influential
	Almaasah et al[29], 2025	0.443	0.417	-0.040	-	Stable
	Shah et al[11], 2024	0.373	0.357	-0.100	-	Influential
Meta-analysis 3: IPSS-post-void residual (Full model r = 0.363; 95%CI: 0.150-0.543)
	None (Full model)	0.380	0.363	-	0.150-0.543	Reference
	Ko et al[13], 2010	0.398	0.381	+0.018	-	Stable
	Cakiroglu[31], 2013	0.375	0.359	-0.004	-	Stable
	Aisuodionoe-Shadrach et al[32], 2020	0.384	0.367	+0.004	-	Stable
	Hamza et al[10], 2021	0.390	0.373	+0.010	-	Stable
	Mbouché et al[1], 2022	0.413	0.393	+0.030	-	Stable
	Anyimba et al[3], 2023	0.369	0.354	-0.009	-	Stable
	Apata et al[5], 2023	0.405	0.386	+0.023	-	Stable
	Kohler and Kausik[16], 2023	0.404	0.386	+0.023	-	Stable
	Nketiah et al[6], 2024	0.409	0.390	+0.027	-	Stable
	Shah et al[11], 2024	0.356	0.342	-0.021	-	Stable
	Fazal et al[12], 2025	0.291	0.283	-0.080	0.105-0.444	Influential

¹Δr: Change in pooled r relative to the full model (reference row). New pooled r was calculated using the Restricted Maximum Likelihood random-effects model on the remaining k - 1 studies. 95% confidence intervals marked - were positive across all iterations; full values available in Supplementary Table 1. Stable:|Δr| < 0.05 and no change in direction or significance; Influential: |Δr| ≥ 0.05.

IPSS: International Prostate Symptom Score; CI: Confidence interval.

Table 6 Exploratory subgroup analysis by geographic region and sample size: Pooled correlation coefficients across all three meta-analyses

Meta-analysis	Subgroup factor	Category	k	Pooled r	95%CI	I2	Notes
IPSS-QoL	Geographic region	South Asia (India, Nepal)	3	Approximately 0.75	0.66-0.91	-	Higher upper bound; includes study with r = 0.91
		Africa (Nigeria, Ghana)	2	Approximately 0.65	0.54-0.76	-	Numerically lower; both estimates are still large-effect
	Sample size	Large (n > 100)	4	Approximately 0.68	0.54-0.76	-	More stable; consistent effect
		Small (n ≤ 100)	1	0.910	-	N/A	Single study[23]; interpret with caution
PV-IPSS	Geographic region	Africa (Nigeria, Cameroon)	3	0.22	0.01-0.41	-	Substantially lower; storage-symptom dominance
		South/Southeast Asia (India, Bangladesh, Indonesia)	6	0.52	0.35-0.66	-	Consistent moderate-to-large effect
		Pakistan	3	0.51	0.32-0.66	-	Comparable to South/Southeast Asia
	Sample size	Small (n < 100)	5	0.44	0.22-0.63	-	Wider CI; includes influential study[29]
		Large (n ≥ 100)	7	0.46	0.30-0.61	-	More stable and representative
IPSS-PVR	Geographic Region	Africa (Nigeria, Ghana, Cameroon)	6	0.262	0.079-0.425	54.3%	Moderate heterogeneity within subgroup
		Pakistan	2	0.738	0.461-0.882	High	Only k = 2; tertiary referral bias likely
		East Asia (Korea)	1	0.200	0.090-0.305	N/A	Single study[31]
		Western (United States, Turkey)	2	0.220	0.121-0.313	Low	Earlier disease detection; diverse LUTS aetiology
	Sample Size	Large (n > 200)	4	0.178	0.094-0.259	31.2%	Large, representative samples; more conservative
		Small (n ≤ 200)	7	0.446	0.261-0.604	68.1%	Small-study effect; higher and more variable estimates

k: Number of studies in subgroup; Pooled r: Back-transformed correlation from variance-weighted random-effects pooling (τ² carried from full model); 95% confidence interval on r scale; I²: Within-subgroup heterogeneity. Subgroup analyses are exploratory; formal between-subgroup Q-tests were unavailable for all analyses. -: Insufficient k for meaningful I² estimation. Subgroup estimates should be interpreted with caution, given the small k per subgroup. An omnibus between-subgroup Q-test was not generated by the variance-weighted pooling procedure; however, the principal pre-specified regional contrast (Africa vs South/Southeast Asia for Prostate volume-International Prostate Symptom Score) was tested formally on Fisher’s Z scale and was statistically significant (Z = 2.29, P = 0.022).

IPSS-QoL: International Prostate Symptom Score-quality of life; PV-IPSS: Prostate volume-International Prostate Symptom Score; IPSS-PVR: International Prostate Symptom Score-post-void residual; CI: Confidence interval.

Table 7 Narrative synthesis: Key clinical findings and practice implications derived from primary studies included in the meta-analysis¹

Ref.	Country	Key clinical findings	Practice implications
Kohler and Kausik[16], 2023	United States	IPSS has statistically significant but weak correlations with Qmax, voided volume, and PVR in an unselected population (n = 1014); subjective symptom severity does not reliably predict objective voiding parameters	Holistic assessment mandate: Clinical and reimbursement pathways must integrate subjective symptom scores with objective voiding profiles; surgical decision-making must not be based on symptom scores alone
Mbouché et al[1], 2022	Cameroon	IPP correlates more strongly with low Qmax and AUR risk than with overall prostate volume; IPP grade > 10 mm confers significantly elevated obstruction risk, even with modest total PV	Diagnostic standardization: Ultrasound protocols for LUTS/BPH should mandate systematic IPP measurement and grading alongside PV and PVR; IPP is non-invasive, adds no equipment cost, and improves prognostic accuracy
Taneja et al[7], 2017; Timilsina et al[23], 2024	India/Nepal	High illiteracy rates render the IPSS difficult to complete without clinician assistance; the pictogram-based VPSS correlates strongly with IPSS and uroflowmetry parameters and takes less time to complete unaided	Tool adaptation: VPSS should be adopted as a first-line or co-administered assessment tool in developing nations and low-literacy populations to eliminate interviewer bias and improve the accuracy of symptom scoring
Anyimba et al[3], 2023	Nigeria	Interviewer-assisted IPSS administration introduces systematic reporting bias, attenuating the observed correlation between reported symptoms and objective Qmax/PVR in low-literacy settings	Minimizing measurement bias: Healthcare policies in low-resource settings must account for interviewer-assisted questionnaire subjectivity; objective ultrasonographic imaging and VPSS adoption should be prioritized as complementary tools
Awaisu et al[9], 2021	Nigeria	Patients present late because LUTS are falsely attributed to normal ageing; PV correlates significantly with IPSS at presentation (r = 0.179), reflecting delayed healthcare-seeking and low BPH community literacy	Public health and early triage: Community education campaigns are needed to decouple LUTS from “normal agein” where uroflowmetry is unavailable, PV combined with IPSS serves as a practical triage tool for urgency of referral
Fazal et al[12], 2025	Pakistan	Strong IPSS-PVR correlation (r = 0.920) in a tertiary referral population with advanced disease; UTIs are highly prevalent in older BPH patients with severe LUTS and elevated residual urine volumes	Comorbidity management: BPH protocols must incorporate routine urine culture and sensitivity testing for all patients with PVR ≥ 100 mL, even without overt infective symptoms; microbiological surveillance alongside ultrasonography is clinically imperative
Ngwa-Ebogo et al[24], 2023	Cameroon	Weak-to-moderate PV-IPSS correlation (r = 0.410); confirms that prostate size is a poor standalone predictor of symptom bother; large volume does not reliably indicate severe or treatment-requiring LUTS	Surgical criteria refinement: PV alone is insufficient for clinical or surgical decision-making; guidelines should require composite assessment - incorporating symptom score, uroflowmetry, PVR, and IPP grade - rather than volume thresholds in isolation
Shah et al[11], 2024	Pakistan	Strong correlations between IPSS and both PV (r = 0.779) and PVR (r = 0.599) in a tertiary urology population with advanced disease burden at presentation	Tertiary care pathway: The strength of IPSS correlations in tertiary settings reflects advanced-stage disease, not baseline population parameters; policies should prioritize earlier primary care intervention to reduce disproportionate burden on tertiary facilities

¹Practice implications derived from primary study findings within the context of current European Association of Urology/American Urological Association guidelines. All studies were cross-sectional unless otherwise stated. AUR: Acute Urinary Retention; BPH: Benign prostatic hyperplasia; IPP: Intravesical prostatic protrusion; IPSS: International Prostate Symptom Score; PV: Prostate volume; PVR: Post-void residual; Qmax: Maximum urinary flow rate; QoL: Quality of life; UTI: Urinary tract infection; VPSS: Visual Prostate Symptom Score; LUTS: Lower urinary tract symptoms.