Table 2:

Baseline characteristics of patients with relatively high estimated glomerular filtration rate

CharacteristicDrug; no. (%) of patients*Standardized difference relative to nitrofurantoin, %
Nitrofurantoin n = 70 758Ciprofloxacin n = 29 095Norfloxacin n = 45 116TMP–SMX n = 37 665CiprofloxacinNorfloxacinTMP– SMX
Age, yr, mean ± SD75 ± 775 ± 776 ± 775 ± 7381
Year of cohort entry
 2002–200518 091 (25.6)7 037 (24.2)20 452 (45.3)15 383 (40.8)34233
 2006–200925 745 (36.4)11 588 (39.8)16 078 (35.6)12 958 (34.4)724
 2010–201326 922 (38.0)10 470 (36.0)8 586 (19.0)9 324 (24.8)44329
Rural residence7 522 (10.6)3 171 (10.9)5 025 (11.1)6 589 (17.5)1220
Prescription supply of 3–7 d57 679 (81.5)21 331 (73.3)35 385 (78.4)29 476 (78.2)2088
Health care use, mean ± SD§
 Primary care visits8.99 ± 7.99.37 ± 8.19.26 ± 8.08.50 ± 7.4547
 Emergency department visits3.19 ± 3.73.25 ± 3.53.04 ± 3.23.12 ± 3.4383
 Hospital discharges1.77 ± 1.31.85 ± 1.51.81 ± 1.41.81 ± 1.4844
 Urine cultures5.08 ± 6.35.72 ± 7.15.55 ± 6.64.41 ± 5.6161219
Prior antibiotic prescriptions
 012 159 (17.2)4 208 (14.5)6 639 (14.7)7 034 (18.7)774
 1 or 220 718 (29.3)7 818 (26.9)12 634 (28.0)11 716 (31.1)534
 3 or 414 083 (19.9)5 696 (19.6)8 943 (19.8)7 488 (19.9)100
 ≥ 523 798 (33.6)11 373 (39.1)16 900 (37.4)11 427 (30.3)1187
Comorbidities**
 Coronary artery disease††19 573 (27.7)9 053 (31.1)13 941 (30.9)10 328 (27.4)871
 Dementia5 421 (7.7)2 290 (7.9)3 325 (7.4)2 618 (7.0)113
 Diabetes mellitus‡‡9 413 (13.3)4 171 (14.3)5 429 (12.0)4 603 (12.2)343
 Heart failure5 695 (8.0)2 654 (9.1)4 009 (8.9)2 998 (8.0)430
 Peripheral vascular disease495 (0.7)220 (0.8)360 (0.8)276 (0.7)110
 Stroke1 337 (1.9)588 (2.0)918 (2.0)672 (1.8)111
 Urinary incontinence§§2 205 (3.1)892 (3.1)1 381 (3.1)1091 (2.9)001
Baseline medications ¶¶
 No. of unique medications, mean ± SD5.02 ± 3.605.36 ± 3.754.97 ± 3.534.69 ± 3.44919
 ACE inhibitor19 334 (27.3)7 926 (27.2)12 606 (27.9)10 429 (27.7)011
 ARB10 638 (15.0)4 899 (16.8)6 192 (13.7)4 715 (12.5)547
 β-Blocker16 878 (23.8)7 258 (24.9)11 170 (24.8)8 778 (23.3)321
 Calcium-channel blocker17 724 (25.0)7 600 (26.1)11 242 (24.9)8 764 (23.3)204
 Loop diuretic4 392 (6.2)2 210 (7.6)3 105 (6.9)2 264 (6.0)531
 Potassium-sparing diuretic3 619 (5.1)1 625 (5.6)2 860 (6.3)2 241 (6.0)254
 Thiazide diuretic13 726 (19.4)5 256 (18.1)8 855 (19.6)7 871 (20.9)314
Prescriber characteristics
 Sex, female26 409 (37.3)8 036 (27.6)12 297 (27.3)10 813 (28.7)211218
 Time since graduation, yr, mean ± SD23.69 ± 10.826.60 ± 10.827.54 ± 10.123.90 ± 11.112151
  • Note: ACE = angiotensin-converting enzyme, ARB = angiotensin II receptor blocker, SD = standard deviation, TMP–SMX = trimethoprim–sulfamethoxazole.

  • * Unless otherwise indicated.

  • Standardized differences are less sensitive to sample size than traditional measures for testing hypotheses. They provide a measure of the difference between groups divided by the pooled SD, where a value greater than 10% is considered to represent a meaningful difference. (25)

  • Municipalities with population < 10 000 were considered to be rural.

  • § Health care use (except for primary care visits) was assessed as the mean number of visits by a patient in the preceding 5 years.

  • Primary care visits were assessed as the mean number of visits by a patient in the preceding year.

  • ** Comorbidities were assessed for the preceding 5 years.

  • †† Coronary artery disease includes undergoing coronary artery bypass graft surgery or percutaneous coronary intervention and diagnosis of angina.

  • ‡‡ Diabetes mellitus was assessed through use of oral hypoglycemic medications and insulin prescriptions in the preceding 120 days.

  • §§ Urinary incontinence was assessed through prescriptions for overactive bladder medication in the preceding 120 days.

  • ¶¶ Baseline medications were assessed for the preceding 120 days.