European Journal of Cardiovascular Medicine

Surgery is accompanied by psychological as well as physiological stress. Anxiety before an operation commonly reflects concern about anaesthesia, postoperative pain, surgical outcome, disability, loss of control, and unfamiliar hospital surroundings. Its intensity varies widely among patients and is influenced by demographic, clinical, and psychosocial factors. In adults scheduled for elective procedures, high preoperative anxiety has been associated with female sex, greater trait anxiety, depressive symptoms, pre-existing pain, and higher perioperative risk status.[1] The clinical relevance of this response extends beyond subjective distress because anxiety can modify autonomic activity, attention to nociceptive signals, pain appraisal, and behavioural responses during recovery.[2]

Postoperative pain is a multidimensional experience generated by tissue injury but shaped by cognitive and affective factors. Even patients undergoing similar operations can report markedly different pain intensities and require different amounts of analgesic medication. Prospective work has identified preoperative pain, anxiety, age, surgical procedure, and psychological distress among important predictors of acute postoperative pain or analgesic consumption.[3,4] In breast surgery, greater preoperative anxiety and depression were associated with higher pain intensity and opioid use during the first postoperative day.[5] Likewise, anxiety and pain catastrophizing have shown independent or interacting relationships with postoperative pain severity.[6] These observations support the concept that perioperative pain cannot be explained solely by the magnitude of surgical injury.

Validated anxiety instruments allow this psychological component to be quantified before surgery. The State-Trait Anxiety Inventory distinguishes transient state anxiety from the more stable tendency to experience anxiety and has been extensively used in perioperative research.[1,4,10] Studies in obstetric, paediatric, and mixed surgical populations have reported links between higher preoperative anxiety and less favourable postoperative recovery, including greater pain, increased analgesic use, and reduced satisfaction.[7,8] A qualitative systematic review involving more than 23,000 patients identified preoperative anxiety as a significant predictor of postoperative pain, while broader psychological distress was associated with analgesic consumption.[9] Subsequent investigations have also demonstrated that anxiety can predict anaesthetic requirements and pain sensitivity, reinforcing the relevance of psychological screening to perioperative planning.[10]

Despite this evidence, anxiety assessment is not routinely incorporated into preoperative evaluation in many resource-limited clinical settings, and Indian data from heterogeneous elective surgical populations remain limited. A simple preoperative measure that identifies patients at risk of greater postoperative pain could facilitate anticipatory counselling, closer pain surveillance, and timely multimodal analgesia. Therefore, the present prospective observational study was conducted to determine the association between preoperative state anxiety and postoperative pain outcomes in adults undergoing elective surgery. The primary objective was to compare postoperative VAS pain scores between patients with high and lower preoperative anxiety. Secondary objectives were to examine the relationship of preoperative anxiety with time to first rescue analgesia and cumulative 24-hour analgesic requirement, and to determine whether preoperative anxiety remained independently associated with these outcomes after adjustment for relevant demographic and perioperative factors..

Study design and setting

This prospective observational study was conducted in the Department of Anaesthesiology, Konaseema Institute of Medical Sciences and Research Foundation, Amalapuram, Andhra Pradesh, India, from January to June 2016. The hospital is a tertiary-care teaching centre providing elective surgical and anaesthesia services. Preoperative anxiety was the exposure of interest, while postoperative pain and rescue analgesic use were the principal outcomes; clinical management was not altered by anxiety status.

Participants and sampling

Adults aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I-III scheduled for elective surgery under general or neuraxial/regional anaesthesia were screened consecutively. Exclusion criteria were emergency surgery, inability to complete anxiety or pain scales, diagnosed major psychiatric illness or regular anxiolytic/antidepressant therapy, chronic opioid use or persistent pain requiring daily analgesics, and incomplete perioperative data. For an anticipated correlation of 0.35, two-sided alpha of 0.05, and 80% power, approximately 62 evaluable participants were required by Fisher z transformation. The target was increased to 80 completed cases to improve precision and allow for incomplete assessments.

Preoperative anxiety assessment

Age, sex, body mass index (BMI), ASA physical status, anaesthetic technique, and duration of surgery were recorded. Before premedication on the day of surgery, state anxiety was measured with the 20-item State-Trait Anxiety Inventory-State (STAI-S), which ranges from 20 to 80, with higher scores indicating greater situational anxiety.[1,4,10] An STAI-S score >44 was prespecified as high anxiety; scores <=44 defined the lower-anxiety group.

Postoperative pain and analgesic assessment

Anaesthesia was administered according to departmental protocols. Postoperative pain was measured on a 0-10 visual analogue scale (VAS) at 6, 12, and 24 hours. Rescue analgesia was given when VAS was >=4 or on patient request. Time from completion of surgery to the first rescue dose was recorded. Cumulative analgesic administration during the first 24 hours was abstracted from medication records and expressed as milligrams of tramadol equivalent according to departmental conversion practice. The number of patients receiving at least two rescue doses was also documented.

Statistical analysis

Continuous variables are presented as mean ± standard deviation and categorical variables as number and percentage. Independent-samples t tests compared continuous outcomes between anxiety groups; chi-square or Fisher exact tests were used for categorical variables. Pearson correlation quantified associations of continuous STAI-S scores with postoperative outcomes. Multivariable linear regression assessed associations with 6-hour VAS and 24-hour analgesic requirement after adjustment for age, sex, BMI, ASA physical status, anaesthetic technique, and duration of surgery. Adjusted coefficients are reported with 95% confidence intervals. Two-sided P<0.05 indicated statistical significance.

Ethical considerations

Necessary Permissions were obtained before starting the study. Written informed consent was obtained from all participants, and the study followed institutional ethical standards and the Declaration of Helsinki.

During the study period, 86 patients scheduled for elective surgery were assessed for eligibility. Six were excluded: three did not satisfy the predefined eligibility criteria, two declined participation, and one had incomplete perioperative data. Thus, 80 patients were included in the final analysis, and complete preoperative anxiety, postoperative pain, and analgesic requirement data were available for the analytic cohort.

The mean age of the study population was 44.6 ± 13.2 years, and 44 (55.0%) participants were male. The mean BMI was 25.8 ± 3.6 kg/m². Most patients were classified as ASA physical status I or II. General anaesthesia was used in 47 (58.8%) patients, while 33 (41.3%) received regional/spinal anaesthesia. The mean duration of surgery was 96.4 ± 31.7 minutes (Table 1).

Table 1. Baseline demographic and perioperative characteristics of the study participants (n=80)

Values are expressed as mean ± SD or n (%). BMI: body mass index; ASA: American Society of Anesthesiologists.

The mean preoperative STAI-S score was 43.7 ± 9.5. Thirty-four patients (42.5%) had high preoperative anxiety (STAI-S >44), whereas 46 (57.5%) were in the lower-anxiety category. Postoperative pain was greatest at the earliest assessment and declined over 24 hours. The overall mean VAS scores were 3.6 ± 1.4 at 6 hours, 3.1 ± 1.3 at 12 hours, and 2.3 ± 1.1 at 24 hours. Mean time to the first rescue analgesic was 5.3 ± 2.4 hours, and mean cumulative 24-hour rescue analgesic use was 107.1 ± 43.8 mg tramadol equivalent. Thirty-one patients (38.8%) required at least two rescue doses (Table 2).

Table 2. Preoperative anxiety, postoperative pain, and analgesic outcomes (n=80)

STAI-S: State-Trait Anxiety Inventory-State; VAS: visual analogue scale; SD: standard deviation.

Postoperative pain was significantly greater among patients with high preoperative anxiety. At 6 hours, mean VAS was 4.3 ± 1.2 in the high-anxiety group compared with 3.1 ± 1.2 in the lower-anxiety group (P<0.001). The difference persisted at 12 hours (3.7 ± 1.2 vs. 2.6 ± 1.1; P<0.001) and 24 hours (2.7 ± 1.1 vs. 2.0 ± 0.9; P=0.003). Patients with high anxiety required rescue analgesia earlier, with a mean time to first dose of 4.1 ± 1.8 hours compared with 6.2 ± 2.4 hours in the lower-anxiety group (P<0.001). Their cumulative 24-hour analgesic requirement was also higher (132.4 ± 41.6 vs. 88.4 ± 35.7 mg tramadol equivalent; P<0.001). Two or more rescue doses were required by 55.9% of high-anxiety patients and 26.1% of lower-anxiety patients (P=0.007) (Table 3).

Table 3. Comparison of postoperative outcomes according to preoperative anxiety status

Values are mean ± SD or n (%). STAI-S: State-Trait Anxiety Inventory-State; VAS: visual analogue scale.

Correlation analysis showed a significant positive association between preoperative STAI-S score and pain intensity. STAI-S correlated with VAS at 6 hours (r=0.52, P<0.001), 12 hours (r=0.49, P<0.001), and 24 hours (r=0.34, P=0.002). Higher anxiety was also associated with greater cumulative 24-hour analgesic requirement (r=0.47, P<0.001). Conversely, anxiety showed a significant inverse correlation with time to first rescue analgesia (r=-0.43, P<0.001), indicating that more anxious patients tended to require analgesia earlier (Table 4).

Table 4. Correlation of preoperative anxiety score with postoperative pain and analgesic requirement

VAS: visual analogue scale. Positive r values indicate that higher STAI-S scores were associated with higher pain/analgesic requirement; the negative r for rescue timing indicates earlier analgesia with higher anxiety.

On multivariable linear regression, preoperative STAI-S remained independently associated with 6-hour postoperative pain after adjustment for age, sex, BMI, ASA physical status, anaesthetic technique, and duration of surgery. Each one-point increase in STAI-S was associated with a 0.07-point increase in 6-hour VAS score (adjusted beta=0.07, 95% CI 0.04-0.10; P<0.001). Higher STAI-S was also independently associated with greater cumulative 24-hour analgesic requirement (adjusted beta=1.86 mg tramadol equivalent per STAI-S point, 95% CI 0.93-2.79; P<0.001) (Table 5).

Table 5. Adjusted association of preoperative STAI-S score with principal postoperative outcomes

Models were adjusted for age, sex, BMI, ASA physical status, type of anaesthesia, and duration of surgery. CI: confidence interval; BMI: body mass index; ASA: American Society of Anesthesiologists.

The present prospective observational study found a clinically important association between preoperative state anxiety and acute postoperative pain. More than two-fifths of participants had STAI-S scores above 44. Compared with patients with lower anxiety, this group reported higher VAS pain scores at 6, 12, and 24 hours, required rescue analgesia earlier, consumed more analgesic medication during the first postoperative day, and more frequently needed multiple rescue doses. Continuous STAI-S scores correlated moderately with early pain intensity and 24-hour analgesic requirement. These associations persisted after adjustment for age, sex, BMI, ASA physical status, anaesthetic technique, and surgical duration.

Our findings agree with earlier prospective evidence. Caumo et al. identified anxiety and other presurgical characteristics as predictors of moderate-to-intense postoperative pain after abdominal surgery.[3] Kalkman et al. demonstrated that preoperative clinical and psychological variables could improve prediction of severe early postoperative pain.[4] In women undergoing breast cancer surgery, Ozalp et al. observed higher pain intensity and analgesic consumption in patients with greater preoperative anxiety and depression.[5] Granot and Ferber also reported that anxiety and pain catastrophizing contributed to postoperative pain prediction.[6] Together, these studies support a biopsychosocial model in which tissue injury interacts with affective arousal, expectation, attention, and coping processes to shape postoperative pain.

The present results are also consistent with larger evidence syntheses. Ip et al., reviewing 48 studies involving more than 23,000 patients, identified preoperative anxiety as a significant predictor of postoperative pain and psychological distress as a predictor of analgesic consumption.[9] Kil et al. found that anxiety was related to postoperative pain and anaesthetic requirements in women undergoing thyroidectomy.[10] Theunissen et al. further demonstrated an association between preoperative anxiety or catastrophizing and chronic postsurgical pain.[11] Procedure-specific analyses have emphasized that patient characteristics and surgical factors jointly influence pain severity.[12] Thus, anxiety should be interpreted as one component of a broader perioperative risk profile rather than as an isolated determinant.

The inverse relationship between anxiety and time to first rescue analgesia adds practical relevance. Greater anxiety can heighten vigilance toward bodily sensations, intensify threat appraisal, and lower pain tolerance, leading to earlier recognition or reporting of clinically important pain. Raichle et al. found that preoperative anxiety was associated with acute pain after lower-limb amputation even after accounting for pain and analgesic use.[13] Gorkem et al. similarly reported that high state anxiety independently predicted postoperative pain and pethidine consumption after elective caesarean delivery.[14] Because anxiety is easily measurable before surgery, brief screening can identify patients who need focused counselling, realistic expectation-setting, closer postoperative surveillance, and individualized multimodal analgesic planning. Randomized trials are required to determine whether targeted anxiety-reduction interventions directly improve postoperative analgesic outcomes.

LIMITATIONS

This study was conducted at a single tertiary-care centre with a modest sample and included heterogeneous elective procedures and anaesthetic techniques. Surgical category, baseline pain sensitivity, pain catastrophizing, socioeconomic factors, and detailed intraoperative analgesic exposure were not incorporated into the adjusted models. Anxiety was assessed at one preoperative time point, and follow-up was restricted to 24 hours; therefore, chronic postsurgical pain and longer-term recovery were not evaluated.

Preoperative state anxiety was significantly associated with acute postoperative pain intensity and rescue analgesic requirement in adults undergoing elective surgery. Patients with STAI-S scores above 44 reported higher VAS pain scores at 6, 12, and 24 hours, required analgesia earlier, and consumed more analgesic medication during the first postoperative day. These relationships remained significant after adjustment for major demographic and perioperative variables. Incorporating a brief anxiety assessment into routine preanaesthetic evaluation can identify patients at greater risk of difficult postoperative pain control. Patients with elevated anxiety can then receive focused counselling, realistic expectation-setting, closer pain surveillance, and individualized multimodal analgesic planning to support a smoother early postoperative recovery and comfort.

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