Background

Suicide continues to be a growing public health issue, and suicidal behaviors have been identified as a critical problem in the military population, with the number of soldiers dying by suicide exceeding those killed in action.

Objective

This study aimed to characterize the population with attempted or completed suicides at the South Texas Veterans Health Care System and to analyze differences between those 2 populations. Other outcomes included adherence to psychiatric medications 6 months before suicide attempt or completion and psychiatric hospitalizations, psychiatric emergency department visits, and “no-show” appointments to mental health providers.

Methods

Data were collected from the Suicide Prevention and Application Network for patients from South Texas Veterans Health Care System who had attempted or completed suicide between September 1, 2011, and September 30, 2013. Those data were supplemented with data from the computerized patient-record system. A retrospective chart review was conducted to collect further information.

Results

Of 120 events included in the analysis, there were 97 attempts (81%) and 23 completions (19%). Men were significantly more likely to complete a suicide than women were (P = .025). Those that attempted suicide were more likely to have previous attempts compared with those who completed suicide (mean of 1.01 versus 0.17 respectively, P = .0035). The most frequent method for attempt was toxic ingestion (accounting for 61.9% of attempts), while the most frequent method of completing suicide was by using a firearm (87.0%); there was a statistically significant difference found between methods used for suicide attempt versus completion (P < .0001). Significantly more attempts than completions involved alcohol (21 versus 0 respectively; P = .013). Those on divalproex were less likely to complete suicide (16 attempts, 0 completions; P = .040). There were no differences between groups for the secondary outcomes studied.

Conclusions

Characteristics associated with completion of suicide in this analysis include male gender and using a firearm, while having previous attempts, being on divalproex, or using alcohol are associated with being more likely to attempt rather than complete suicide. More information is needed on how to appropriately identify high-risk veterans, and suicide safety plans should be developed for these patients to minimize their risk.

Suicide continues to be a growing public health issue. In September 2014, the World Health Organization1  published its first global report on suicide prevention and called for coordinated action to reduce suicides worldwide. That report highlighted suicide as a global phenomenon that is preventable. According to data the Centers for Disease Control and Prevention2-3  published in 2012, suicide was the third leading cause of death among persons aged 15 to 24 years, second among persons aged 25 to 34 years, fourth among person aged 35 to 54 years, and the eighth among person 55 to 64 years. Suicide accounts for 20% of all deaths annually among those 15 to 24 years old. Poisoning is the leading cause of suicide for females, whereas males are more likely to commit suicide with a firearm. In addition, suicide results in high economic costs, estimated at US$34.6 billion and US$6.5 billion in combined medical and work-loss costs for suicide and nonfatal, self-inflicted injuries, respectively.2-3 

Suicidal behaviors have been identified as a critical problem in the military population, with the number of soldiers dying by suicide exceeding those killed in action.4-5  In June 2013, the Veterans Affairs (VA) and the Department of Defense (DoD) published the Practice Guideline for Assessment and Management of Patients at Risk for Suicide,6  which provides a framework for formally assessing a patient who may be at risk of suicide and identifying immediate and long-term management strategies. The goal of suicide prevention is the reduction of risk factors and strengthening of protective factors (Table 1).2  However, the causes of suicide are complex, and the contributing factors are many. There is ongoing research to help identify risk factors among varying populations.3  To better characterize suicides among current or former military personnel, the Centers for Disease Control and Prevention has been working with the National Violent Death Reporting System to link the DoD Suicide Event Report and the VA to the National Violent Death Reporting System.8  In addition, since 2008, the VA has mandated that health systems track attempted and completed suicides in a national database, the Suicide Prevention and Application Network (SPAN). The SPAN database allows for ongoing surveillance of suicide attempts among veterans. In 2012, the VA published a Suicide Data Report,9  containing preliminary information on suicide among veterans to improve prevention programs and outcomes for veterans at risk. However, that report contained information from only 21 states and did not include Texas.9 

TABLE 1: 

Risk factors and protective factors for suicide7

Risk factors and protective factors for suicide7
Risk factors and protective factors for suicide7

Although national data on suicide among veterans is still being compiled, other literature has been published providing guidance on how to best help this at-risk population. Suicidal ideations are thought to be more dangerous in war veterans than in the general population because they often have the knowledge to use firearms; therefore, any ideation in veterans should be taken seriously. Among war veterans, suicidal ideations are often associated with posttraumatic stress disorder (PTSD) and depression, which are often coexisting conditions that increase the risk of suicidality more than either condition alone.4  Also, PTSD has been shown to be a risk factor for suicidal ideation in American veterans of the wars in Iraq and Afghanistan. These veterans who screened positive for PTSD were more than 4 times as likely to endorse suicidal ideation relative to veterans without PTSD, and the risk for suicidal ideation increased to 5.7 times greater for those who screened positive for 2 or more comorbid mental disorders in comparison to those with only PTSD.10  Given this information, it is important to appropriately screen and treat these mental health conditions to potentially prevent suicide attempts. There is also thought to be an increased risk of suicide after discharge from a psychiatric hospitalization in the general population and among service members, highlighting the need for aggressive safety planning in this population.11-13  The VA/DoD guidelines for the management of patients at risk for suicide recommend the development of an individualized safety plan for all persons who are at high, acute risk for suicide as part of discharge planning.6  In addition, according to the 2010 DoD Suicide Event Report, one quarter of service members who committed suicide saw a mental health provider in the preceding 30 days.14 

Despite some evidence in the literature regarding suicide risk among veterans, there is a continued need for more information on suicide attempts and completions among this population to develop more-effective suicide prevention programs. The results of this study may be used to inform providers at the South Texas Veterans Health Care System (STVHCS) of the characteristics and outcomes of the patients who attempted suicide to increase understanding of suicide on a local level.

This project was approved by the local institutional review board (expedited review) and VA Research and Development.

Subjects

Patients who attempt or complete suicide are entered into the suicide surveillance and clinical support system organized by the suicide prevention coordinators on a local level. Included patients were those who were entered into that database at the STVHCS from September 1, 2011, to September 30, 2013. Patients without a clear suicide attempt or completion were excluded. Examples of excluded patients included those who had only serious suicidal ideation without attempt and those whose autopsy results were inconclusive for suicide.

Outcomes

The primary outcome was to characterize the study population who attempted or completed suicide at the STVHCS during the study time frame. Secondary outcomes included medication-possession ratios (MPRs) for psychiatric medications, hospitalizations, emergency department visits, and “no-show” appointments with mental health providers for the 6 months before suicide attempt or completion by those who attempted or completed suicide.

Data Collection

Data provided by the suicide prevention coordinator and analyzed included the following: name, date of birth, era of service, Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) status, military era, sex, psychiatric diagnoses, previous suicide attempts, method used, whether suicide had been addressed (in most recent mental health progress notes), whether a suicide safety plan was in place, whether the patient was followed in the mental health department, and if so, whether the patient had been seen in the previous 7 or 30 days.

Those data were supplemented with data from the computerized patient record system through a retrospective chart review. Additional information collected included psychiatric medications used during the review period, including psychiatric MPRs for 6 months before the suicide attempt. The MPRs were calculated manually using the prescription refill history available in CRPS. The following equation was used15-16 :

formula

Also collected were the number of psychiatric hospitalizations, psychiatric emergency department visits, and no-show appointments to mental health providers 6 months before the suicide attempt or completion.

Statistical Analysis

Microsoft Excel (Microsoft Corporation, Redmond, WA) and JMP Pro 10 (SAS Institute, Cary, NC) software were used for descriptive statistics and to compare differences between those who attempted versus those who completed suicide. The Fisher exact test and the Pearson χ2 test were used for continuous data, and 1-way analysis of variance (ANOVA) tests were used for nominal data.

As illustrated in Figure 1, 139 events were included in the suicide surveillance and clinical support system at the STVHCS during the study time frame. Nineteen (14%) of those events were excluded; 15 of the 19 events (79%) were suicidal ideation without suicide attempt or completion, 3 patients (16%) had an undetermined cause of death, and 1 patient (5%) could not be found in the computerized patient record system. That left 120 events included in the analysis of the study; of which, there were 97 attempts (81%) and 23 completions (19%). In the attempt group, there were 8 patients (8%) who had 2 attempts during the study time frame, and 1 patient (1%) who had 3 attempts; of these patients with multiple attempts, 2 patients (66%) completed suicide on their second attempt.

FIGURE 1:

Included and excluded patients

FIGURE 1:

Included and excluded patients

Close modal

Primary Outcome

The primary outcome of this study was to characterize the population who attempted and completed suicide at the STHVCS during the study time frame. Information collected on these groups of patients is summarized in Table 2. The mean (SEM) age of patients was 43.9 (1.43) and 47.9 (2.92) years in the attempt and completion groups, respectively (P = nonsignificant). Most patients were male (94 of 120; 78.3%), and statistically, men were significantly more likely to complete suicide than were women (P = .025). Most patients who attempted or completed suicide were veterans of the OEF/OIF era, and the most frequent mental health diagnosis was depression, followed by PTSD, and substance abuse, although there was no statistical difference among groups for military era or mental health diagnoses.

TABLE 2: 

Population characteristics

Population characteristics
Population characteristics

Those that attempted suicide were more likely to have previous attempts compared with those who completed suicide (mean [SEM], 1.01 [0.12] versus 0.17 [0.25], respectively; P = .0035). Fifteen patients (13%) in the study population were first seen at the STVHCS for suicidal thoughts; therefore, there were no previous opportunities to assess for suicide. Out of the remaining patients (n=105), 85 (81%) had suicidality assessed, defined as having suicide addressed in the last mental health note, before attempt or completion. That left 20 patients (19%) who did not have suicide addressed at their last mental health visit; 3 of those 20 (15%) went on to complete suicide. Although most patients did have suicide addressed before their attempt or completion, most patients did not have a suicide safety plan in place (38% of attempts, 30% of completions; P = nonsignificant).

Method Used in Suicide Attempts and Completions

Figure 2 summarizes the methods that patients used to attempt or complete suicide. The most frequent method for attempt was toxic ingestion (629%; 60 of 97 attempts). No patients who completed suicide did so by toxic ingestion. The most frequent method of completing suicide was by using a firearm (87%; 20 of 23). There was a statistically significant difference found between methods used for suicide attempt versus completion (P < .0001). Significantly more attempts than completions involved alcohol, based on the information available in the medical record (21 of 97 [22%] versus 0 of 23 [0%], respectively; P = .013).

FIGURE 2:

Method of suicide attempt or completion

* Other = suffocation, n = 3; motor-vehicle, n = 2; self-inflicted burn, n = 1; jump from height, n = 1

b Fisher exact test.

c Pearson χ2 test

FIGURE 2:

Method of suicide attempt or completion

* Other = suffocation, n = 3; motor-vehicle, n = 2; self-inflicted burn, n = 1; jump from height, n = 1

b Fisher exact test.

c Pearson χ2 test

Close modal

Secondary Outcomes

Table 3 summarizes the secondary outcomes, which included comparing MPRs for psychiatric medications, hospitalizations, emergency department visits, and no-show appointments with mental health providers in the 6 months before suicide attempt or completion for those who attempted or completed suicide; 61% (59 of 97) and 74% (17 of 23) of patients who attempted or completed suicide, respectively, were on psychiatric medications in the 6 months preceding the suicide attempt or completion (P = nonsignificant); 91% (69 of 76) of patients in the study groups who were on a psychiatric medication were on an antidepressant. The only significant difference found was that those patients on divalproex were less likely to complete suicide (16 attempts, 0 completions; P = .040). Neither the MPR nor the MPR coefficient of variation was significantly different between groups, although there were low numbers of patients in these groups that had information that allowed this calculation (n = 40 [41%] in attempt group, n = 11 [48%] in completion group). There was also no difference between groups for no-show for appointments to psychiatry, emergency department visits, or psychiatric hospitalizations 6 months before suicide attempt or completion.

TABLE 3: 

Secondary outcomes

Secondary outcomes
Secondary outcomes

As expected in the VA population, most patients in the study were men, and men were more likely than women to complete suicide. Additionally, most patients had a mental health diagnosis, were engaged with mental health services, and had a previous suicide attempt, all consistent with known risk factors for suicide. Most patients did have suicide addressed before their attempt or completion. A case-control study17  of suicide risk assessments for 488 veterans who died by suicide was conducted and published in 2013. It was found that most VA patients with a history of depression received some suicide risk assessment within the preceding year, but suicide risk assessments were infrequently administered at the final visit of patients who eventually died by suicide. Those authors suggested that assessment and prevention strategies that are less dependent on disclosure of suicidal ideations are needed.17  Suicide safety plans should typically be developed collaboratively following a comprehensive suicide risk assessment as an intervention strategy to lower the risk of suicidal behavior.18  They are designed to give the patient the necessary tools to manage a crisis and to engage other resources and are recommended in the VA/DoD guidelines for the management of patients at risk for suicide.6  Important components of a safety plan include recognizing warning signs, employing internal coping strategies, using social contacts and social settings, contacting mental health professionals, and restricting access to lethal methods.6  In this study, despite having suicide addressed, most patients did not have a suicide safety plan in place, which may be an area of possible improvement. This may be especially true because there was a significant difference in methods used for attempts versus completions; most attempts were by toxic ingestion, and most completions were with a firearm. Part of a suicide safety plan is reducing the potential for use of lethal methods, which may include safely storing medication, implementing safe firearm procedures, or restricting access to knives or other lethal methods.18  In addition, significantly more attempts than completions involved alcohol; the reason for this is unknown but may be an artifact of documentation and the patient being able to recall details of the event.

Overall, the evidence for the use of pharmacotherapy to address suicide risk is limited.6  In this study population, most patients were on a psychiatric medication. The appropriateness of the prescribed medications was beyond the scope of this study, but an important part of managing self-harm behavior or suicide risk is appropriately identifying and treating psychiatric illness.5  Divalproex was the only medication that showed a statistically significant difference (those on divalproex were less likely to complete suicide). Large population-based studies have shown lower rates of suicide attempts in patients treated with lithium than attempts by those treated with anticonvulsants (including divalproex).19,20  This effect was not seen in this study, but that was likely due to the few patients on lithium (n = 2; 2%). Lithium's antisuicidal properties are thought to be partially due to its effects on impulsivity, and valproate has also been used to treat impulsivity in patients with behavior disorders and cluster B personality disorders.21-23  This may be important because impulsive tendencies increase a patient's risk for suicide. Despite this, it is important to consider the US Food and Drug Administration (FDA) warnings that antiepileptic drugs are associated with increased risk of suicidality in placebo-controlled trials.24  Therefore, divalproex should not be routinely recommended to prevent suicidality but should be used appropriately in accordance with its FDA-approved indications.

Because most patients in the study were on a psychiatric medication, it is also important that adherence to those prescriptions be assessed. There are a variety of measures that can be used to calculate refill adherence; many of which produce identical or very similar results.25  Although no one calculation has been identified as the “gold standard” when reporting adherence, literature suggests that it is important to disclose all adherence calculations.26  The MPR calculation used in this study calculated adherence percentage, which was adjusted to include the final refill period. Although administrative data can be helpful in estimating medication adherence, there are certainly limitations that should be considered. The calculation provides the highest possible level of adherence, and some literature27-28  suggests that patient-reported adherence and administrative data calculations do not correlate. In this study, the MPR and MPR coefficient of variation were not statistically different between groups. Additionally, both groups had MPRs greater than 80%, which is frequently reported in the literature as a cutoff for acceptable adherence.26  For the remaining secondary outcomes, there was also no significant difference among groups.

Although suicide risk and protective factors for the general population have been identified, there is less evidence available specifically for the VA population, although some is available. In 2012, systematic chart reviews were conducted29  for 423 veteran suicides, and it was found that veterans with sleep disturbance died sooner from suicide than did those without sleep disturbance, after adjustment for the presence of mental health or substance use symptoms, age, or region. The authors suggested that sleep disturbance might provide an important intervention target for at-risk veterans.28  In addition, in 2014, a sample of 110 depressed veterans was evaluated30  through diagnostic interviews and self-report questionnaires, and “life meaning” was significantly associated with suicidal ideations. Larger studies are needed that continue to investigate suicide risk factors among veterans to identify risk factors in this unique patient population.

Limitations

Given the retrospective design of this study, there are a variety of limitations. A power analysis was not completed; therefore, the sample size required to find a difference is not known. Perhaps the most important limitation in this study is that statistically significant findings do not suggest causality based on the study design. However, the findings do provide potential areas for future consideration and clinical concern. This study compared 2 high-risk populations, but there was no control group, which may have limited statistically significant findings. In addition, the study focused on only 2 years of data at STVHCS; therefore, the study was not all-encompassing and cannot be extrapolated to other health systems. No accounting was made for medications, emergency department visits, and hospitalizations outside of the STVHCS. In addition to the limitations of MPR calculations reviewed in the discussion, MPRs were manually calculated, introducing the risk for human error. The correlation between the number of psychiatric medications a patient was prescribed and the tendency to attempt or complete suicide was not studied. Lastly, there were a variety of risk factors and protective factors that were not analyzed in this study, including impulsive or aggressive tendencies, history of trauma, and social stressors or support. It would be difficult, although possible, to account for some of these factors by performing a more thorough chart review and reviewing suicide risk assessments, assuming there was consistent and accurate documentation in place.

Characteristics associated with completion of suicide in this analysis included male sex and use of a firearm, whereas having previous attempts, being on divalproex, or using alcohol at the time of the event are associated with being more likely to attempt, rather than complete, suicide. More information is needed on how to appropriately identify high-risk veterans, and suicide safety plans should be developed for these patients to minimize their risk.

The authors wish to thank Dr Stephen Saklad for his assistance with the statistical analysis of this project. This study was supported by resources and the use of facilities at the South Texas Veterans Health Care System in San Antonio, Texas.

1
World Health Organization
.
First WHO report on suicide prevention [Internet]
.
Geneva
:
WHO
.
c2014 [cited
2014
.
2
Centers for Disease Control and Prevention
.
Atlanta, GA: National Center for Injury Prevention and Control
. c2010
[cited
2012
Oct 19].
Web-based Injury Statistics Query and Reporting System (WISQARS)
[Internet].
.
3
Centers for Disease Control and Prevention
.
Atlanta, GA: National Center for Injury Prevention and Control
. c2009
[cited
2013
Sep 1].
Suicide prevention
[Internet].
.
4
Sher
L
,
Braquehais
MD
,
Casas
M.
Posttraumatic stress disorder, depression, and suicide in veterans
.
Cleve Clin J Med
.
2012
;
79
(
2
):
92
-
7
. DOI: . PubMed PMID: 22301558.
5
Hoge
CW
,
Castro
CA.
Preventing suicides in US service members and veterans: concerns after a decade of war
.
JAMA
.
2012
;
308
(
7
):
671
-
2
. DOI: . PubMed PMID: 22893160.
6
The Assessment and Management of Risk for Suicide Working Group
.
VA/DoD clinical practice guideline for assessment and management of patients at risk for suicide. Version 1.0
.
Washington
:
Department of Veterans Affairs and Department of Defense;
2013
.
7
National Suicide Prevention Lifeline
.
Suicide risk factors
.
[cited
2014
.
8
Centers for Disease Control and Prevention
.
Atlanta, GA: National Center for Injury Prevention and Control, Division of Violence Prevention
. c2010
[cited
2013
Sep 1].
Preventing suicide: program activities guide
. .
9
Kemp
J
,
Bossarte
R.
Suicide data report
,
2012
[Internet]. [cited 2013 Sep 1]
Washington: Department of Veterans Affairs, Mental Health Services, Suicide Prevention Program
. .
10
Jakupcak
M
,
Cook
J
,
Imel
Z
,
Fontana
A
,
Rosenheck
R
,
McFall
M.
Posttraumatic stress disorder as a risk factor for suicidal ideation in Iraq and Afghanistan War veterans
.
J Trauma Stress
.
2009
;
22
(
4
):
303
-
6
. DOI: . PubMed PMID: 19626682.
11
Luxton
DD
,
Trofimovich
L
,
Clark
LL.
Suicide risk among U.S. service members after psychiatric hospitalization, 2001-2011
.
Psychiatr Serv
.
2013
;
64
(
7
):
626
-
9
. DOI: . PubMed PMID: 23677509.
12
Hunt
IM
,
Kapur
N
,
Webb
R
,
Robinson
J
,
Burns
J
,
Shaw
J
,
Appleby
L.
Suicide in recently discharged psychiatric patients: a case-control study
.
Psychol Med
.
2009
;
39
(
03
):
443
-
9
. DOI: . PubMed PMID: 18507877.
13
Qin
P
,
Nordentoft
M.
Suicide risk in relation to psychiatric hospitalization
.
Arch Gen Psychiatry
.
2005
;
62
(
4
):
427
-
32
. DOI: . PubMed PMID: 15809410.
14
National Center for Telehealth and Technology
.
Department of Defense suicide event report
: calendar year
2010
annual report
[Internet]. c2010 [cited 2013 Sep 1].
Washington: Department of Defense
. .
15
Karve
S
,
Cleves
MA
,
Helm
M
,
Hudson
TJ
,
West
DS
,
Martin
BC.
Prospective validation of eight different adherence measures for use with administrative claims data among patients with schizophrenia
.
Value Health
.
2009
;
12
(
6
):
989
-
95
. DOI: . PubMed PMID: 19402852.
16
Fairman
K
,
Motheral
B.
Evaluating medication adherence: which measure is right for your program?
J Manag Care Pharm
2000
;
6
(
6
):
499
-
505
.
17
Smith
EG
,
Kim
HM
,
Ganoczy
D
,
Stano
C
,
Pfeiffer
PN
,
Valenstein
M.
Suicide risk assessment received prior to suicide death by Veterans Health Administration patients with a history of depression
.
J Clin Psychiatry
.
2013
;
74
(
3
):
226
-
32
. DOI: . PubMed PMID: 23561227.
18
Stanley
B
,
Brown
GK.
Safety plan treatment manual to reduce suicide risk: veteran version
[Internet]. [Final version
2008
Aug
20
;
cited 2014 Jun 26].
Washington: US Department of Veterans Affairs
. .
19
Goodwin
FK
,
Fireman
B
,
Simon
GE
,
Hunkeler
EM
,
Lee
J
,
Revicki
D.
Suicide risk in bipolar disorder during treatment with lithium and divalproex
.
JAMA
.
2003
;
290
(
11
):
1467
-
73
. DOI: . PubMed PMID: 13129986.
20
Collins
JC
,
McFarland
BH.
Divalproex, lithium and suicide among Medicaid patients with bipolar disorder
.
J Affect Disord
.
2008
;
107
(
1-3
):
23
-
8
. DOI: . PubMed PMID: 17707087.
21
Kovacsics
CE
,
Gottesman II, Gould TD. Lithium's antisuicidal efficacy: elucidation of neurobiological targets using endophenotype strategies
.
Annu Rev Pharmacol Toxicol
.
2009
;
49
:
175
-
98
. DOI: . PubMed PMID: 18834309.
22
Donovan
SJ
,
Stewart
JW
,
Nunes
EV
,
Quitkin
FM
,
Parides
M
,
Daniel
W
,
Susser
E
,
Klein
DF.
Divalproex treatment for youth with explosive temper and mood lability: a double-blind, placebo-controlled crossover design
.
Am J Psychiatry
.
2000
;
157
(
5
):
818
-
20
.
Erratum in: Am J Psychiatry 2000;157(6):1038; Am J Psychiatry 2000;157(7):1192. PubMed PMID: 10784478
.
23
Hollander
E
,
Tracy
KA
,
Swann
AC
,
Coccaro
EF
,
McElroy
SL
,
Wozniak
P
,
Sommerville
KW
,
Nemeroff
CB.
Divalproex in the treatment of impulsive aggression: efficacy in cluster B personality disorders
.
Neuropsychopharmacology
.
2003
;
28
(
6
):
1186
-
97
. DOI: . PubMed PMID: 12700713.
24
Food and Drug Administration
.
Statistical review and evaluation: antiepileptic drugs and suicidality
[report]. c2008 [updated
2008
May
23
;
cited 2014 Jun 26].
Silver Spring, MD
:
CDER Office of Biostatistics
. .
25
Hess
LM
,
Raebel
MA
,
Conner
DA
,
Malone
DC.
Measurement of adherence in pharmacy administrative databases: a proposal for standard definitions and preferred measures
.
Ann Pharmacother
.
2006
;
40
(
7-8
):
1280
-
88
. DOI: . PubMed PMID: 16868217.
26
Kozma
CM
,
Dickson
M
,
Phillips
AL
,
Meletiche
DM.
Medication possession ratio: implications of using fixed and variable observation periods in assessing adherence with disease-modifying drugs in patients with multiple sclerosis
.
Patient Prefer Adherence
.
2013
;
7
:
509
-
16
. DOI: . PubMed PMID: 23807840.
27
Grossberg
R
,
Zhang
Y
,
Gross
R.
A time-to-prescription-refill measure of antiretroviral adherence predicted changes in viral load in HIV
.
J Clin Epidemiol
.
2004
;
57
(
10
):
1107
-
10
. DOI: . PubMed PMID: 15528063.
28
Guénette
L
,
Moisan
J
,
Préville
M
,
Boyer
R.
Measures of adherence based on self-report exhibited poor agreement with those based on pharmacy records
.
J Clin Epidemiol
.
2005
;
58
(
9
):
924
-
33
. DOI: . PubMed PMID: 16085196.
29
Pigeon
WR
,
Britton
PC
,
Ilgen
MA
,
Chapman
B
,
Conner
KR.
Sleep disturbance preceding suicide among veterans
.
Am J Public Health
.
2012
;
102
(
Suppl 1
):
S93
-
7
. DOI: . PubMed PMID: 22390611.
30
Braden
A
,
Overholser
J
,
Fisher
L
,
Ridley
J.
Life meaning is associated with suicidal ideation among depressed veterans
.
Death Stud
.
2014
;
39
(
1
):
24
-
9
. Epub 2014 Jul 24. DOI: . PubMed PMID: 24932675.