Using Canadian Primary Care Sentinel Surveillance Network data to examine depression in patients with a diagnosis of Parkinson disease: a retrospective cohort study

Kimberly Rose P. Singian; Morgan Price; Vicky Bungay; Sabrina T. Wong

doi:10.9778/cmajo.20160052

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Table 1: Characteristics of patients with Parkinson disease in the Canadian Primary Care Sentinel Surveillance Network

Characteristic	Men, no. (%)* n = 996	Women, no. (%)* n = 819	Overall, no. (%)* n = 1815
Age,† mean ± SD	74.1 ± 11.8	75.1 ± 13.4	74.6 ± 12.4
14-50	29 (2.9)	44 (5.4)	73 (4.0)
51-60	94 (9.5)	55 (6.7)	149 (8.2)
61-70	208 (20.9)	156 (19.1)	364 (20.1)
71-80	341 (34.3)	237 (29.0)	578 (31.9)
81-90	282 (28.4)	258 (31.6)	540 (29.8)
> 90	40 (4.0)	67 (8.2)	107 (5.9)
Age at diagnosis of Parkinson disease,† mean ± SD	70.9 ± 11.7	71.8 ± 12.6	71.3 ± 12.6
Duration of Parkinson disease, yr,† mean ± SD	3.3 ± 2.8	3.4 ± 2.8	3.3 ± 2.8
Encounters with a primary care provider, mean ± SD
1-year period	7.2 ± 9.2	7.9 ± 10.1	7.5 ± 9.6
2-year period	14.7 ± 16.1	16.3 ± 17.3	15.5 ± 16.7
Residence type†
Urban	780 (81.3)	653 (82.3)	1433 (82.0)
Rural	180 (18.8)	135 (17.1)	315 (18.0)
Body mass index†, mean ± SD	27.0 ± 4.8	26.2 ± 5.6	26.7 ± 5.2
Body mass index category	n = 483	n = 370	n = 853
Normal (18-24)	144 (29.8)	144 (38.9)	288 (33.8)
Underweight (< 18)	1 (0.2)	8 (2.2)	9 (1.1)
Overweight (25-29)	202 (41.8)	118 (31.9)	320 (37.5)
Obese (≥ 30)	136 (28.2)	100 (27.0)	236 (27.7)
Smoking status*	n = 451	n = 328	n = 779
Never	223 (49.6)	208 (63.4)	431 (55.3)
Current	47 (10.4)	38 (11.6)	85 (10.9)
Past	181 (40.1)	82 (25.0)	263 (33.8)
No. of comorbidities‡, mean ± SD	1.7 ± 1.2	1.9 ± 1.3	1.8 ± 1.3
0	168 (16.9)	130 (15.9)	298 (16.4)
1	300 (30.1)	234 (28.6)	534 (29.4)
2	281 (28.2)	207 (25.3)	488 (26.9)
≥ 3	247 (24.8)	248 (30.3)	495 (27.3)
Type of comorbidity§	n = 828	n = 689	n = 1517
Hypertension	520 (62.8)	453 (65.8)	973 (64.1)
Depression‡	283 (34.2)	295 (42.8)	578 (38.1)
Osteoarthritis‡	259 (31.3)	313 (45.4)	572 (37.7)
Dementia	245 (29.6)	194 (28.2)	439 (29.0)
Diabetes	232 (19.6)	162 (33.7)	394 (26.0)
COPD†	146 (17.6)	78 (11.3)	224 (14.8)
Epilepsy	26 (3.1)	28 (4.1)	54 (3.6)

Note: COPD = chronic obstructive pulmonary disease, SD = standard deviation.

*Unless otherwise specified.

†Missing data: age, age at diagnosis of Parkinson disease, duration of Parkinson disease and residence type had < 4.0% missing data; body mass index was missing for 53.0% of patients; smoking status was missing for 57.1%.

‡Significance by sex defined as p < 0.05 using t test and χ² of independence test.

§Column percentage is > 100% because patients could have more than 1 chronic condition.

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Table 2: Recorded medications for depression in patients with diagnoses of both Parkinson disease and depression in the Canadian Primary Care Sentinel Surveillance Network

Characteristic	Men, no. (%)* n = 283	Women, no. (%)* n = 295	Overall, no. (%)* n = 578
Age at diagnosis of depression, yr, mean ± SD	71.8 ± 11.9	72.0 ± 12.3	71.9 ± 12.1
Diagnosed before Parkinson disease	121 (42.8)	121 (41.0)	242 (41.9)
Diagnosed after Parkinson disease	162 (57.2)	174 (58.9)	336 (58.1)
Duration of depression, yr, mean ± SD	5.0 ± 3.1	4.8 ± 3.2	4.9 ± 3.2
Encounters with a primary care provider, mean ± SD
1-year period	8.3 ± 9.1	8.6 ± 8.5	8.5 ± 8.8
2-year period	17.2 ± 16.5	17.7 ± 15.6	17.5 ± 16.1
No. of medications for depression, mean ± SD	1.7 ± 1.2	1.9 ± 1.2	1.8 ± 1.2
0	44 (15.5)	36 (12.2)	80 (13.8)
1	76 (26.9)	91 (30.8)	167 (28.9)
2	96 (33.9)	82 (27.8)	178 (30.8)
≥ 3	67 (23.7)	86 (29.2)	153 (26.5)
Type of medication for depression
Selective serotonin reuptake inhibitors	140 (49.5)	162 (54.9)	302 (52.2)
Benzodiazepines and related hypnosedatives	130 (45.9)	143 (48.5)	273 (47.2)
Atypical antipsychotic agents	86 (30.4)	97 (32.9)	183 (31.7)
Serotonin-norepinephrine reuptake inhibitors	45 (15.9)	54 (18.3)	99 (17.1)
Serotonin antagonist and reuptake inhibitors	44 (15.6)	31 (10.5)	75 (13.0)
Tricyclics and tetracyclics	21 (7.4)	36 (12.2)	57 (9.9)
Amitriptyline†	9 (3.2)	17 (6.0)	26 (4.5)
Bipolar medications	24 (8.5)	30 (10.2)	54 (9.3)
Monoamine oxidase inhibitors	5 (1.8)	4 (1.4)	9 (1.6)
No depression medication	44 (15.5)	36 (12.2)	(80) 13.8

Note: SD = standard deviation.

*Unless otherwise specified.

†Tricyclic recommended in Canadian guidelines on Parkinson disease.¹²

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Table 3: Encounter-adjusted Poisson regression of the recorded number of medications for depression by sex in patients with diagnoses of Parkinson disease and depression

Dependent variable*	Sex (male reference = 1.00)		No. of encounters with a primary care provider
Dependent variable*	RR (95% CI)	p value	RR (95% CI)	p value
No. of medications	1.08 (0.95-1.22)	0.2	1.11 (1.06-1.16)	< 0.001*

Note: 95% CI = confidence intervals (lower bound-upper bound), p value = probability value, RR = rate ratio.*Sex served as the main independent variable and number of encounters with a primary care provider in a 2-year period served as a covariate using a log-2 scale in the regression model.

†Significance defined as p < 0.05.

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Table 4: Encounter-adjusted logistic regressions for the recorded type of medications for depression by sex in patients with diagnoses of Parkinson disease and depression

Dependent variable	Sex (male reference = 1.00)		No. of encounters with a primary care provider
Dependent variable	OR (95% CI)	p value	OR (95% CI)	p value
Selective serotonin reuptake inhibitors	1.25 (0.90-1.73)	0.2	1.22 (1.08-1.39)	< 0.01*
Benzodiazepines and related hypnosedative	1.11 (0.80-1.54)	0.5	1.25 (1.10-1.42)	< 0.001*
Atypical and antipsychotic agents	1.12 (0.79-1.59)	0.5	1.10 (0.96-1.25)	0.2
Serotonin-norephinephrine reuptake inhibitors	1.18 (0.77-1.83)	0.4	1.06 (0.90-1.25)	0.5
Serotonin antagonist and reuptake inhibitors	0.64 (0.39-1.04)	0.07	1.14 (0.94-1.38)	0.2
Tricyclics and tetracyclics	1.73 (0.99-3.10)	0.06	1.32 (1.07-1.67)	0.01*
Bipolar medications	1.22 (0.69-2.16)	0.5	1.15 (0.93-1.43)	0.2
Monoamine oxidase inhibitors	0.76 (0.19-2.90)	0.7	1.23 (0.75-2.14)	0.4

Note: CI = confidence intervals, OR = odds ratio.

*Significance defined as p < 0.05.

Gender served as the main independent variable and the number of encounters with a primary care provider in a 2-year period served as a covariate using a log-2 scale in the regression model.