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Table 2 Baseline characteristics

From: Higher dose versus lower dose of antiviral therapy in the treatment of herpes zoster infection in the elderly: a matched retrospective population-based cohort study

 

Unmatched

Matched

 

Higher dosea(n = 73,383)

Lower doseb(n = 3,998)

Standardized differencec

Higher dosea(n = 23,256)

Lower doseb(n = 3,876)

Standardized differencec

Demographics

      

Age, years

75.9 [6.8]

77.0 [7.3]

0.15

76.7 [7.1]

76.7 [7.1]

0

Women

45,613 (62.2)

2,541 (63.6)

0.03

14,682 (63.1)

2,447 (63.1)

0

Year of cohort entry

      

 2002 - 2003

11,318 (15.4)

514 (12.9)

0.07

3,083 (13.3)

505 (13.0)

0.01

 2004 - 2005

14,016 (19.1)

595 (14.9)

0.11

4,096 (17.6)

572 (14.8)

0.08

 2006 - 2007

14,930 (20.3)

807 (20.2)

0

4,641 (20.0)

779 (20.1)

0

 2008 - 2009

15,783 (21.5)

993 (24.8)

0.08

5,320 (22.9)

964 (24.9)

0.05

 2010 - 2011

17,336 (23.6)

1,089 (27.2)

0.08

6,116 (26.3)

1,056 (27.2)

0.02

Income quintiled

      

 First (lowest)

13,937 (19.0)

831 (20.8)

0.04

4,404 (18.9)

804 (20.7)

0.05

 Second

15,526 (21.2)

802 (20.1)

0.03

4,886 (21.0)

777 (20.1)

0.02

 Third (middle)

14,231 (19.4)

842 (21.1)

0.04

4,469 (19.2)

818 (21.1)

0.05

 Fourth

14,521 (19.8)

751 (18.8)

0.03

4,620 (19.9)

730 (18.8)

0.03

 Fifth (highest)

14,976 (20.4)

755 (18.9)

0.04

4,808 (20.7)

731 (18.9)

0.05

 Missing

192 (0.26)

17 (0.43)

0.03

69 (0.3)

16 (0.4)

0.02

Rural locatione

10,864 (14.8)

505 (12.6)

0.06

3,027 (13.0)

491 (12.7)

0.01

Modified Charlson scoref

      

 0

53,431 (72.8)

2,731 (68.3)

0.10

16,623 (71.5)

2,684 (69.3)

0.05

 1

8,024 (10.9)

445 (11.1)

0.01

2,560 (11.0)

428 (11.0)

0

 2

6,350 (8.7)

400 (10.0)

0.05

2,086 (9.0)

383 (9.9)

0.03

 ≥3

5,578 (7.6)

422 (10.6)

0.10

1,987 (8.5)

381 (9.8)

0.04

Co-morbiditiesg

      

 CKDh

3,799 (5.2)

425 (10.6)

0.20

1,896 (8.2)

316 (8.2)

0

 Chronic liver disease

2,420 (3.3)

138 (3.5)

0.01

735 (3.2)

135 (3.5)

0.02

 COPD

2,994 (4.1)

212 (5.3)

0.06

1,010 (4.3)

198 (5.1)

0.04

 CADi

25,840 (35.2)

1,548 (38.7)

0.07

8,427 (36.2)

1,478 (38.1)

0.04

 Diabetes mellitusj

11,016 (15.0)

699 (17.5)

0.07

3,636 (15.6)

671 (17.3)

0.05

 Heart failure

8,469 (11.5)

611 (15.3)

0.11

2,985 (12.8)

571 (14.7)

0.06

 Stroke/TIA

1,556 (2.1)

109 (2.7)

0.04

513 (2.2)

99 (2.6)

0.02

 Herpes zoster (eye)

89 (0.12)

8 (0.20)

0.02

30 (0.13)

8 (0.21)

0.02

Antiviral type

      

 Acyclovir

4,095 (5.6)

297 (7.4)

0.08

1,692 (7.3)

282 (7.3)

0

 Valacyclovir

29,482 (40.2)

2,694 (67.4)

0.57

15,528 (66.8)

2,588 (66.8)

0

 Famciclovir

39,806 (54.2)

1,007 (25.2)

0.62

6,036 (26.0)

1,006 (26.0)

0

Medicationsk

      

 Anticonvulsants

3,079 (4.2)

178 (4.5)

0.01

988 (4.3)

167 (4.3)

0

 Gabapentin

420 (0.57)

24 (0.60)

0

137 (0.59)

22 (0.57)

0

 Antidepressants

11,201 (15.3)

663 (16.6)

0.04

3,756 (16.2)

636 (16.4)

0.01

 Antipsychotics

1,431 (2.0)

88 (2.2)

0.02

503 (2.2)

86 (2.2)

0

 Barbituates

115 (0.16)

7 (0.18)

0

45 (0.19)

7 (0.18)

0

 Benzodiazepines

13,794 (18.8)

809 (20.2)

0.04

4,446 (19.1)

774 (20.0)

0.02

 Histamine2-receptor antagonists

6,191 (8.4)

337 (8.4)

0

1,911 (8.2)

325 (8.4)

0.01

 Dopamine agonists

326 (0.44)

22 (0.55)

0.02

124 (0.53)

22 (0.57)

0

 Muscle relaxants

399 (0.54)

25 (0.63)

0.01

132 (0.57)

25 (0.64)

0.01

 Opioids

15,738 (21.5)

957 (23.9)

0.06

5,076 (21.8)

923 (23.8)

0.05

 Overactive bladder medications

2,169 (3.0)

149 (3.7)

0.04

704 (3.0)

142 (3.7)

0.04

Prescribing physician

      

 General practitioner

55,723 (75.9)

3,015 (75.4)

0.01

17,671 (76.0)

2,925 (75.5)

0.01

 Ophthalmologist

272 (0.37)

28 (0.70)

0.05

90 (0.39)

27 (0.70)

0.04

 Neurologistl

41 (0.06)

≤5 ( − )

( − )

12 (0.05)

≤5 ( − )

( − )

 Other

7,538 (10.3)

372 (9.3)

0.03

2,350 (10.1)

360 (9.3)

0.03

 Missing

9,809 (13.4)

581 (14.5)

0.03

3,133 (13.5)

562 (14.5)

0.03

  1. Data presented as number (percent) except for age which is presented as mean [standard deviation].
  2. Abbreviations: CAD Coronary Artery Disease, CKD Chronic Kidney Disease, COPD Chronic Obstructive Pulmonary Disease, TIA Transient Ischemic Attack.
  3. aHigher dose of antiviral defined as 4,000 mg/day for acyclovir, 3,000 mg/day for valacyclovir, and 1,500 mg/day for famciclovir.
  4. bA lower dose of antiviral defined as 3,200 mg/day, 2,400 mg/day, 1,600 mg/day or 800 mg/day for acyclovir, 2,000 mg/day, 1,500 mg/day, 1,000 mg/day, or 500 mg/day for valacyclovir, and 1,000 mg/day, 500 mg/day, or 350 mg/day for famciclovir.
  5. cStandardized differences are less sensitive to sample size than traditional hypothesis tests. They provide a measure of the difference between groups divided by the pooled standardized difference; a value >10% (0.1) is interpreted as a meaningful difference between the groups [35].
  6. dIncome was categorized into quintiles based on average neighbourhood income on the index date.
  7. eRural location indicates a population <10,000.
  8. fAssessed with an algorithm using diagnosis codes from hospitalizations in the five years prior; patients with no hospitalizations during this period were given a value of zero.
  9. gCo-morbid diagnoses were ascertained from administrative database codes in the five years preceding the index date.
  10. hIdentified individuals with chronic kidney disease using an algorithm of diagnosis codes validated in our region for older adults [28]. The algorithm identified patients with a median estimated glomerular filtration rate (eGFR) of 38 mL/min per 1.73 m2 (interquartile range 27 to 52), whereas its absence identified patients with a median eGFR of 69 mL/min per 1.73 m2 (interquartile range 56 to 82).
  11. iCoronary artery disease includes receipt of coronary artery bypass graft surgery, percutaneous coronary intervention, and diagnoses of angina.
  12. jIdentified individuals with diabetes through medication use including oral hypoglycemic and insulin.
  13. kMedication use was assessed in the 180 days prior to the index date.
  14. lDue to privacy issues, values ≤5 are suppressed.
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BMC Pharmacology and Toxicology

ISSN: 2050-6511

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