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Table 1 Characteristics of mental health specialty visits for development sample (January 1, 2009 – September 30, 2014) and prospective validation sample (January 1, 2015—September 30, 2017)

From: Empirical evaluation of internal validation methods for prediction in large-scale clinical data with rare-event outcomes: a case study in suicide risk prediction

Characteristic

Development dataset (N = 9,610,318 visits)

Prospective validation dataset (N = 3,754,137 visits)

N

%

N

%

Female

6,081,526

64.1

2,406,695

64.1

Age

 17 or younger

1,048,533

10.9

417,977

11.1

 18–29

1,562,616

16.3

670,337

17.9

 30–44

2,453,898

25.5

948,716

25.3

 45–64

3,510,438

36.5

1,242,067

33.1

 65 or older

1,034,813

10.8

475,040

12.7

Race

 White

6,627,544

69.0

2,511,547

66.9

 Asian

448,590

4.7

192,284

5.1

 Black

836,479

8.7

324,852

8.7

 Hawaiian/Pacific Islander

108,410

1.1

32,803

0.9

 Native American

92,312

1.0

35,824

1.0

 More than one

3,298

0.03

1,788

0.1

 Other race recorded

48,800

0.5

20,879

0.6

 Not race recorded

1,444,885

15.0

634,160

16.7

Ethnicity

 Hispanic

2,183,742

22.7

987,061

26.3

Insurance type

 Commercial group

7,275,199

75.7

2,544,926

67.8

 Individual

325,139

3.4

141,234

3.8

 Medicare

1,409,742

14.7

572,476

15.2

 Medicaid

406,606

4.2

413,007

11.0

 Other

193,632

2.0

82,494

2.2

PHQ-9 9th item response1

 0, Not at all

590,468

6.1

743,288

19.8

 1, Several days

121,483

1.3

153,671

4.1

 2, More than half the days

43,697

0.5

46,977

1.3

 3, Nearly every day

31,408

0.3

32,410

0.9

 Not recorded

8,823,262

91.8

2,777,791

74.0

 PHQ-9 recorded in the previous year

1,296,856

13.5

1,623,943

43.3

Diagnoses in past 5 years, including index visit

 Depression

7,257,525

75.5

2,852,694

76.0

 Anxiety

6,734,366

70.1

2,967,524

79.0

 Bipolar depression

1,317,629

13.7

474,897

12.6

 Schizophrenia

400,713

4.2

154,590

4.1

 Other psychosis

537,050

5.6

221,351

5.9

 Dementia

96,751

1.0

54,782

1.5

 Attention deficit disorder

1,151,179

12.0

485,877

12.9

 Autism spectrum disorder

131,900

1.4

65,795

1.8

 Personality disorder

1,961,027

20.4

603,400

16.1

 Alcohol use disorder

1,561,302

16.2

553,027

14.7

 Drug use

1,654,129

17.2

588,481

15.7

 Post-traumatic stress disorder

845,842

8.8

400,959

10.7

 Eating disorder

350,320

3.6

144,204

3.8

 Traumatic brain injury

312,516

3.3

140,940

3.8

Prescription fills in past 5 years

 Antidepressants

6,521,196

67.9

2,559,147

68.2

 Benzodiazepines

4,536,960

47.2

1,641,900

43.7

 Hypnotics

1,427,849

14.9

381,353

10.2

 2nd generation antipsychotics

2,035,084

21.2

799,401

21.3

Encounters in prior 5 years with mental health diagnosis

 Inpatient

2,296,579

23.9

859,640

22.9

 Outpatient

8,789,642

91.5

3,431,776

91.4

 Emergency department

3,167,119

33.0

1,347,840

35.9

 Suicide attempt in prior 5 years

381,591

4.0

172,329

4.6

Charlson comorbidity index

 0

7,133,017

74.2

2,719,729

72.4

 1

1,402,435

14.6

565,038

15.1

  > 1

1,074,866

11.2

469,370

12.5

Suicide death within 90 days of visit

2318

24 per 100,000

710

19 per 100,000

  1. 1The PHQ-9 9th item asks patients about the frequency of thoughts of suicide or death in the prior 2 weeks