Positive Predictive Values of Procedure Codes on the Treatment of Non-Muscle Invasive Bladder Cancer in the Danish National Patient Registry

Figures & data

Figure 1 Sampling flow.

Abbreviations: N, sample size, number of individuals; NMIBC, non-muscle invasive bladder cancer; TURB, transurethral bladder resection; PDD, photodynamic diagnosis; BCG, bladder instillation with Bacillus Calmette vaccine; MMC, bladder instillation with chemotherapy/Mitomycin C.

Table 1 Codebook ICD-10 Codes in the DNPR Used in NMIBC Treatment

Procedure	ICD-10 Code	Further Specification
TURB	KKCD32
PDD	KZXF45	Additional code
Perioperative MMC	BJHE12/BJHE12A	Code for TURB required registered within 24 hours before BJHE12/BJHE12A
BCG	BJHE11
MMC	BJHE12/BJHE12A

Abbreviations: ICD-10, The International Classification of Diseases, 10th Revision; DNPR, Danish National Patient Registry; NMIBC, Non-muscle invasive bladder cancer; TURB, Transurethral resection of the bladder; PDD, Photodynamic diagnosis; BCG, Bladder instillation whit Bacillus Calmette vaccine; MMC, Bladder instillation with chemotherapy/Mitomycin C.

Table 2 Positive Predictive Values of the Procedure Codes in the Operative Procedure

	Sampling	Verified/Reviewed	PPV (95% CI)
TURB
Overall	125	87/88	98.9% (93.8; 100.0)
Calendar Year
2002–2008	61	28/28	100.0% (87.7; 100.0)
2009–2013	30	26/27	96.3% (81.0; 99.9)
2014–2017	34	33/33	100.0% (89.4; 100.0)
PDD
Overall	25	23/24	95.8% (78.9; 99.9)
Calendar Year
2002–2008	1	1/1	–
2009–2013	13	11/12	91.7% (61.5; 99.8)
2014–2017	11	11/11	100.0% (71.5; 100.0)

Abbreviations: TURB, Transurethral resection of the bladder; PPV, Positive predictive value; CI, Confidence interval; PDD, Photodynamic diagnosis.

Table 3 Negative Predictive Values of the PDD- and the Perioperative Single-Shot MMC Codes

	Sampling	Verified Negative/Reviewed	NPV (95% CI)
PDD
Overall	125	57/88	64.8% (54.4; 73.9)
Calendar Year
2002–2008	61	25/28	89.3% (72.8; 96.3)
2009–2013	30	16/27	59.3% (40.7; 75.5)
2014–2017	34	16/33	48.5% (32.5; 64.8)
Single-shot MMC
Overall	125	86/88	97.7% (92.1; 99.4)
Calendar Year
2002–2008	61	27/28	96.4% (82.3; 99.3)
2009–2013	30	26/27	96.3% (81.7; 99.3)
2014–2017	34	32/33	97.0% (84.7; 99.5)

Abbreviations: PDD, Photodynamic diagnosis; NPV, Negative predictive value; CI, Confidence interval; Single-shot, Refers to the perioperative procedure (within 24 hours from the transurethral resection of the bladder) of one bladder instillation with MMC; MMC, Bladder instillation with chemotherapy/Mitomycin C.

Table 4 Positive Predictive Values of the Adjuvant Instillation Treatment Codes

	Sampling	Verified/Reviewed	PPV (95% CI)
BCG
Overall	25	18/20	90.0% (68.3; 98.8)
Calendar Year
2002–2008	5	1/1	–
2009–2013	10	8/9	88.9% (51.8; 99.7)
2014–2017	10	9/10	90.0% (55.5; 99.7)
MMC
Overall	19	9/13	69.2% (38.6; 90.9)
Calendar Year
2002–2008	6	1/1	–
2009–2013	3	2/2	–
2014–2017	10	6/10	60.0% (26.2; 87.8)

Abbreviations: BCG, Bladder instillation whit Bacillus Calmette vaccine; PPV, Positive predictive value; CI, Confidence interval; MMC, Bladder instillation with chemotherapy/Mitomycin C.